I haven't used computers as long as some in this thread, but I have used computers for about 20 years. First PC was an 80386 SX 16 MHz with 4 MB RAM and 42 MB harddrive.
My mom bought a laptop with Vista Home Premium on it. Apart from the general learning curve, where I learn from doing once, and she learns from me repeating it 15 times to her... I have never seen so much trouble with a laptop. She bought an upgrade DVD which I installed for her. A week later, I had to do a complete re-install of her system. Next week, I had to spend 5 hours reading information on the Net about how to get her network to work in 7. A few days later, I had to do maintenance. Next week, she had problems with IE8. Another 2 hours reading on the Net. The week after, the "Genuine Windows crapdate" came, and her legal system was flagged as pirated. Took me 8 hours to sort through. A few days later, I had to do a re-install of Thunderbird for her, and went to find the e-mail files and configuration files. These are hidden files. I spent 3 hours researching the Net for how to view hidden files and folders. You CAN'T! Even following a Microsoft Knowledge Base-article didn't work! I downloaded a free file manager program, and 5 minutes later it was done. UAC keeps popping up when you least expect it. It won't accept anti-virus software without giving a BSOD.
During the XP-years I migrated my six computers to Ubuntu and haven't looked back since. I am debating whether or not I'll even do any assistance for Windows anymore. The ONE thing I have found that Ubuntu can't do, which I coincidentally find to be a feature, is play DRM-ed video. Everything else, it does as good or better, as fast or faster, as Windows XP/Vista/7.
And the best part of Ubuntu over Windows, IMO? I USE THE SYSTEM, I DON'T MAINTAIN IT! Once a week I install updates (for ALL my programs), and that's it. Takes anywhere from 2 minutes to 20 minutes. With any Windows version out there, I use at least 6 hours a week doing CCleaner, defragging, virus scans, malware scans, updating definitions files, install updates (for Windows only!), search for updates to programs I've installed, and so on and so forth.
And networking in Windows is a joke. I did 3 network-setups on 3 computers, side-by-side by reading a Knowledge Base-article. It took me 2 hours. The only difference I did on them, was give them separate names, as is proper. After 2 hours, I found that 2 of the computers could share ONE folder on each machine, and the third couldn't see or be seen by the network. In Ubuntu, from an empty (or Windows-infested) PC to interconnectivity to all six machines, I use about 1 - 1 1/2 hours, depending on the speed of the machine. That's from inserting the CD, boot it, install the system, remove programs I don't need, install everything I DO need, set up network connection and join my LAN, set up file- and foldersharing and setting the shared files and folders to automount as drives upon start-up.
I spent about 8 years with Windows, routers and several PCs, without EVER getting network to function properly, even when following manuals. It took me 6 months to learn to set up a network in Ubuntu by rote.
And the price tag on 7? Boy, that's a great sales pitch! How can you justify spending 1NOK on a CD-R to burn a Linux distro when you can spend 1200NOK on a DVD filled with bugs and annoyances and "fancy graphics"? And you can even spend more if you feel like it! Ultimate only costs 2500NOK! All you need to run Ultimate is a computer priced around 8000NOK, and you're good to go! Who wants to re-use their old computer anyway? I must be the dumbest person ever to think I can do anything with a P3... Who would want to save money when all you really need is a browser, mediaplayer, and a text-program? And how can you beat Microsoft's support-system priced at 800NOK for 3 e-mails, 1500NOK for 30 mins of live person-to-person phone calls (not including cost of phone call)? Who, in their right mind, thinks other users actually knows anything and can help you with your problem? And noone minds it when we make your system "phone home" to tell us what you've been doing since yesterday. Who would want to control their own system when Micro$oft does such a great job of doing it for you? Who wouldn't mind getting a message saying you can no longer use your system because Micro$oft found out that you used their system to make a movie criticising them? (The End-User License Agreement, which you don't get to see or read before inserting the installation disc in the computer, and having opened the package, already have accepted, actually gives them that "right")
Now, seeing as this poll was about Windows 7, I've bashed Windows and Microsoft. But most of what I've said here actually applies to every member of the Business Software Alliance. Haven't heard of them? They're the MPAA and RIAA and IFPI and BPI and so on and so forth, for software companies that insert DRM in their products, sue for patent infringement because they patented the idea of "tabs". They never used it, but they patented the idea, so you better pay up, or else! (Tabs is just an example, but their patents are actually that stupid)
To round this all off: I've used EVERY version of Microsoft OS and Office product from DOS 5.0. The last OS Microsoft released that actually was any good, was DOS 6.22. With it, I managed to expand the abilities of my 80386 so much, I could fit nearly 750 MB worth of software on that 42MB harddrive, and I managed to tweak the settings such that I could actually run games made for a Pentium 90 (not without SOME lagging, but it was playable).
The last time I had a similar experience was when I first used Ubuntu on a (then) 7-year old laptop, a Pentium 366MHz with 192MB RAM and 6.2GB harddrive. It ran XP, but took 10 min to boot. It had no network card, and was one of the first laptops to have a CD-drive. After I installed Ubuntu, I did a speed test alongside an XP-system, clean install except for OpenOffice. The XP-system was a P4 1GHz with 1.5 GB RAM and 200GB harddrive. After clicking to open OpenOffice Writer, the XP-system took a little over a minute to start it. The same OpenOffice Writer-version on Ubuntu took about 45 seconds to start. And I managed to get networking on it by hooking a USB-cable to my cable-modem and ticking off in Network Manager that the (single) USB 1.1 port was a network port. When I tried the same in XP, I had to install a driver for 20 minutes, fail, remove, re-install, fail, search the Net at a friend's house for instructions, download a newer driver, install, and fail. Wouldn't work.
There are so many reasons why I don't think Windows is worth the price of the cardboard box, regardless of which version it is. But as a "newer and better" version of Windows comes out every now and then, I have to test it because I am my social circle's computer-guru. And every time a new version comes, I get bigger and bigger headaches. Literally. After my sessions with my mom's computer, you can find me in a dark room, lying down, crying after having taken painkillers to get rid of the headache. You may ask why I'm crying? I'm smart, I'm computer literate, I have played with computers for over 20 years, and up until Vista, there wasn't a problem I couldn't figure out. Now, a simple thing like locating and looking at hidden files and folders are beyond me. In my Ubuntu machines, it's two mouse-clicks or two key-presses. In W7 I had to search the Net for an alternate file-manager and learn a new program's quirks before I could do that.