I used Windows for years and years, and I just recently added a Mac to the home network. It is now the primary computer I use. I am happy with the Mac! (Not so happy with the Windows computers, but the function fine on XP; I wouldn't consider Vista at all.) It took me maybe a year to get fully used to using XP (and there are still more technical things about it I continue to discover every time I need to fix a problem with it), but I was comfortable with Mac OS X Tiger within a few weeks.
Now don't consider me a big Mac fanboy or anything, I just like them better, and from everything I see, Mac OS X actually is the superior OS, and I don't like it when people say incorrect statements which indicate the opposite. So...
I have seen all the arguments for not switching to a Mac, and I can counter all of them, mainly because they are based on incorrect or outdated, or just non-existent information.
"Macs are":
More expensive: You can get a PC for cheap, but it will be slow and virtually unusable with software installed. iMacs and MacBooks go for about $1200 and up, but even these lower-end ones perform very well. Plus, with all the other things you need to buy for a PC, even the lower-end ones come out more expensive than Macs. You need to buy a screen for desktops. You need to buy internet security subscriptions. You may need to buy Microsoft Office for hundreds of dollars (iWork for Macs is like $70). You will probably also need to spend some good money on computer repairs and tech support. Altogether, you will be spending much more on any PC than on the Macs.
Macs are less productive: Sorry, do you care to explain to me why iWork has 4.5 stars and MS Office has 3 stars on Amazon.com? And with the constant security pop-ups from your internet security program or Vista, as well as constant Windows Updates, coupled with the slower speed of Vista, and likely Vista compatibility issues, I think it is obvious that Macs, which don't have these problems, allow you to be far more productive than in Windows.
Macs are not more secure: Hmm... according to PC World, 20 percent of Windows-based machines have a virus or worm, and 80 percent have spyware or adware. 0 percent of Mac OS X based computers have this, and Macs don't need to slow the computer down with anti-virus software while they're at it. Plus, they come with a built-in firewall that doesn't keep on popping up un-needed warnings and questions.
Macs aren't good for gaming: Not true anymore! Big gaming companies like EA and id are now making their games for Macs as well as Windows. Plus, with BootCamp (or now even Parallels or VMware Fusion), you can get an installation of Windows running on your Mac to run the highest-end games.
Macs don't have a lot of programs that work with them: Wrong again. Maybe this was true over five years ago, but more and more programs are being made mac-compatible. If there is anything you need to do on a Mac, there is a program to do it with. Now, it is uncommon for a program to be Windows-only, and most of these programs are now being ported to Mac. And like I said in the previous paragraph, you can install programs to get Windows software to work side-by-side Mac applications if you need.
Macs aren't faster: That's just a joke. If you get a fresh installation of Windows XP SP3 (when it comes out) with no extra software installed, I'm sure it will work just as fast as a Mac. But after time, after you install programs that open with the computer start-up, after spyware fills up the computer, after the registry gets errors, after the drive gets fragmented, after you get internet security software to make sure nothing you don't want is happening, it will be far, FAR slower than any Mac.