I have been a Windows user since Win 1.0 and until June of this year I had never used Macs or OS X.
I, too, was a Microsoft user for ages, but I started back even further in DOS 3.3. I've now been a Mac user coming up on 2 years (January 2010), and I couldn't imagine switching back at this point.
I do run Windows 7 under VMWare Fusion, but only once in awhile. I just don't NEED Windows anymore - OS X does everything I could want it to do. Is it perfect? Of course not - I really don't like the Finder, but have found a workaround in PathFinder (a superior replacement...I just wish I could get the Finder icon off my Dock without weird things happening.)
I hear people say that OS X is much more stable than Windows but I have no stability issues with my Win machines so that is a moot point to me. Of course there is the virus potential but I use the free AV software, AVG, and don't have any virus issues to speak of so, again, it's a moot point for me.
While you may not have stability issues with Windows, there really is no denying that OS X tends to be much more stable. It's based on a muti-user system (UNIX), which has been around since 1969 - That's a 40 year history of reliability, stability and experience that Apple is working off of.
That's also much of the reason why viruses and spyware are nearly non-existent on OS X. I've heard long-time Mac users say that OS 9 and before had plenty of viruses and malware, so it's not that "Macs" don't get viruses, it's that the underlying SYSTEM in OS X makes it hard for viruses to get into the system to begin with.
The first time you download anything from the Internet (or the first time you download an update to an existing program), you're required to enter your password in order to run the software. That alone is worth peace of mind that a program can't just silently download and install without you knowing about it (which is how a LOT of the current crop of nasty malware on Windows tends to work - we service a LOT of computers in a month where a virus has basically cut off 'net access or keeps you from accessing any administrative tools/control panel.)
There's things I really don't care for in OS X. I don't like having the menu bar for every application at the top of the screen instead of the top of the application's window. I don't like that clicking on the red 'X' hides the window but doesn't close the app. I don't like that I can only resize a window from the bottom right corner of the window.
These do take some getting used to, but I've found that having a single menu at the top is a much better method of working - you always know exactly where your menu is at all times. As someone else mentioned, it's like muscle memory, you move your mouse to the top of the screen in *whatever* app you're in, and you find what you need.
About the red X and green "maximizing issues...
The only major keyboard command I use in OS X *is* Command-Q to quit an app. It's easy to remember, and it's a lot faster than moving back to the top of the screen. This is just one that you're going to have to start doing more, and I think you'll come to appreciate how quick and easy it is.
When I was in Windows, I used to keep ALL of my apps maximized, no matter how little space they were using. It was just easier to ALT-TAB through them as a way to choose which app I wanted to use next. Compared to OS X, this is an extremely inefficient way to do things.
OS X uses the idea (in *most* cases...a few apps here and there don't follow this so closely) that "maximize" should make the app big enough to show everything it needs to show on screen. When you have multiple apps open on the same screen, you can quickly choose another app. It's WAY more productive, particularly if you combine it with Spaces (virtual desktops) - I can't get by without Spaces anymore, that's how much more productive I've become with it.
I was a little irked at the resizing issue when I started, but with some experience using it, I find that I don't even *need* to resize nearly as often as I did in Windows, so it's not really an issue for me anymore.
I don't care for the Dock. I think it is ugly and intrusive, taking up too much screen real estate. I know it can be resized but I still don't like it.
Quick Launch was my favorite way to run programs in Windows, and to me, the Dock is just a big Quick Launch "bar" - Just as with QL, I keep my most used programs there, and click to launch. For anything else I need to run, I just use Spotlight (Command-Space) and start typing the name. (For programs I don't remember the name of, I have an Applications stack in the Dock as well...I obviously don't run these programs all that often...)
If you think it takes too much space, you can set it to hide, the same way as you can hide the taskbar in Windows.
Now, I realize that my main "problem" is that I am used to the way I have been doing things in Windows all these years and I'm set in my ways. I am not looking to start a fight or an argument of which OS is better. I am trying to state my honest opinion of some reasons why I don't think OS X is a good fit for ME.
A lot of longtime Mac users may suggest (and a few already have) that you just go back to Windows, but I'd recommend to keep using it, check out some of the programs that have been suggested (PathFinder), and I think you'll eventually find that it's a good system overall - at least worthy of spending your time in without worrying so much about malware or having to drill down so many layers to do things that are easily accessible from System Preferences.
Good luck!