The simple answer is: It is too early to tell if Microsoft security is good enough to protect your new Windows 8 computer.
BUT...
Having personally serviced thousands of computers, I would have to say that NO SINGLE security product will ever offer complete protection. I have worked on infected computers that had virtually every brand on Security software installed on them and I can tell you that you are never 100% safe. I use different security on each of my own personal computers so that I can be familiar with the different brands to be able to better serve my customers and I cannot really say that I have any one overall favorite. The different brands of protection change from year to year and what was once a good product can quickly become a real dog (Just look at the up and down cycles of Norton and McAfee). I have used the Free products from AVG, Avast and Microsoft for years with fairly good results and I must say that the newer versions of Norton have been very good and do not hog computer resources like they once did. I cannot really say that Windows 8 with the New version of Microsoft Defender and Smart Screen is any good or not. It just has not been out long enough. Many users believe that you are better off with the lesser known brands because it might make sense that virus writers would optimize their infections to get through the major Antivirus software brands first before paying any attention to the minor brands.
There are many contributing factors as to why a computer gets infected other than the type of security software that you have installed, the most obvious is your Internet surfing habits. If you are someone that surfs all over the internet researching all kinds of strange topics and aimlessly clicking on links then you will be a lot more likely to get infected than someone who simply uses the Internet to read email and perform some banking transactions. I had a client a few years ago who was writing a book on Maralyn Monroe and Google searching for all kinds of topics such as "Famous Blonds" and "Bucksome Blonds" and he could not figure out why his computer was getting infected almost every other day or two.
Another major factor is which operating system you have. Windows XP is far more likely to get infected than Windows 7. I am guessing or at least hoping Windows 8 is even better, but the jury is still out on that. Linux and Mac OSX are the least likely to get infected but this could start to change as time goes on. Even though I have had very good luck with Microsoft Security Essential (MSE) as a whole, I have had many Windows XP computers with MSE installed come in with really bad infections. I have not had the opportunity to run across any infected Windows 8 computers as yet. But that is not unusual for a new operating system, it took awhile before I saw any infected Windows 7 computer when it first came out.
In the end, Full Security is not a single product but rather a combination of security measures that will only reduce the odds that you will pick up an infection. NOTHING is ever 100%!!!
Here are just a few other factors:
Your Internet Connection - A computer that is directly connected to the Cable Modem is less secure than one that connects through a router. A really good router with a hardware firewall is even better.
Updates - A computer running outdated software and utilities is more likely to get infected.
Microsoft, Apple, Sun and Adobe don't publish updates just for the fun of it. In many cases, they are providing updates to patch a security vulnerability to try to keep you protected. So when you see that Java or Adobe update pop up, don't just ignore them. It is important to always install updates regardless of whether you have a Mac or a PC.
Surfing Habits - I know it is obvious but I have to mention it again. If anyone in the house is surfing for Porn then it is almost guaranteed that you will get infected. Surfing and click on everything in sight is only going to increase your odds of getting infected. Downloading Free video and music from suspicious websites is another big risk and can even be a potential problem when clicking on these type of links in Facebook and other social sites. Simply mistyping the name of common websites can also lead you directly to infected areas. The Bad guys often count on people and kids misspelling websites.
Email and Links - Avoid clicking on links in any email even if you know the person that it is coming from. If you must click on a link, hover your mouse over the link first to reveal the real destination of the link to be sure it is pointing to where you really want to go.
Popup Warnings - Pay close attention to pop up warnings that come up on your screen. Many people get infected because they simply clicked on YES before reading what it was they were saying yes to. Even installing updates like Java and Adobe Flash can often come with unwanted Toolbars and programs that you may not want. Always look for the check boxes to see what they might be including with the update.
When in Doubt, Start Over - If you do end up at a questionable website and you are receiving pop ups and questions that you do not understand. DO NOT CLICK ON ANYTHING... Simply close your browser and start over. Even clicking on "No Thank You" or the "X" on some dialog boxes will allow an infection to install.
GENERAL RECOMMENDATIONS
1. Install only ONE realtime security software such as Windows Defender (Windows 8 Only), Security Essentials, Norton, McAfee, Kaspersky, Trend Micro, Eset, Avira, AVG or Avast (sorry, I know there are other brands too). In this case, 2 is NOT better than 1. Having Multiple security products installed and running at the same time can fight each other, slow down your computer and even cause your computer to crash and freeze. Note: For those of you that have Comcast Internet, they offer Norton Security free to all their subscribers. Some people think that it is automatic but that is not true and you must actually download and install it.
2. If the security product you install does not include a firewall, then install a separate Firewall such as Comodo or ZoneAlarm. Be very careful to only install the firewall and not a total protection version that might include another antivirus program. Again it is important that you have only one antivirus and one Firewall installed and running at the same time.
3. Install and scan once per month with at least one other standalone malware scanner such as Malwarebytes, RogueKiller or HitMan Pro. Do not install the full paid versions of these or install any additional realtime scanners. You only want to scan with the manual scanner and you do not want to install anything that is going to be running in the background. Always download the latest version before scanning. Many times these scanners will find problems that your full time scanner may have missed.
4. Install and scan once per month with a separate rootkit scanner such as Tdsskiller from Kaspersky and/or NPE (Norton Power Eraser) from Symantec. Always download the latest version before scanning. I have working on many computers that come up clean with regular virus scans only to find that they have been infected with a rootkit for a long time that was never found by their regular virus scans.
5. Check for and install any and all updates to Windows, Microsoft Office, Java, Adobe Acrobat and Adobe Flash. To avoid problems with updates I always recommend rebooting your computer BEFORE and AFTER installing updates. This is not mandatory but will reduce your chances of problems.
6. Run a good general file cleaner monthly such as CCleaner, ATF Cleaner or even Microsoft's built-in Disk clean or remove junk and temporary files. Some full security Suites like Norton 360 or Norton that is provided by Comcast for FREE will do this for you automatically.
7. Avoid using any Registry Scanners/Optimizers, many can do more damage than good especially if you do not know exactly what you are doing.
8. And I always have to mention Backup, Backup and Backup again. If you do end up with a bad infection, having a good, solid backup with make life a lot easier.
NOTE: I am sure many of you may be confused about the difference between the new Windows Defender with Smart Screen in Windows 8 and the OLD Windows Defender, Microsoft Security Essentials and Windows Live OneCare. I don't know why but Microsoft seems to like to play with our minds. You know, just like all the versions of Microsoft email programs: Outlook Express, Outlook, Entourage, Windows Mail and Windows Live Mail. Sorry but you are on your own here, this discussion is for another time.
addendum:
Sorry, I just noticed that I forgot to mention that using an alternate DNS service can also help not only to protect your family from pornographic website but also from phishing sites. I have setup Family Shield from OpenDNS for many clients and it has worked very well. It is best to set it up on your router so that every device in your house is protected. Note: This in not virus protection but it does block all your computers from accessing many of the sites that contain porn and many of them are infected sites or lead to infected links
Dana
Wayland Computer
Note: This post was edited by its original author to combine addition information from second post to original. on 01/11/2013 at 11:10 AM PT