As long as you can play SE and DOOM, does it matter?
But as for the look of Linux, Knoppix is a good way to try it out. It just boots straight off the CD, no need to install anything at all. IIRC, it uses KDE as it's desktop environment, but with just about every *NIX variant out there, the graphical interface is X11 with different stuff on top. Most Linux distros use either KDE or GNOME on top, some offer both, and some let you use just X11 (I know Fedora does this). Try it out, and see if you like it.
Reasons not to switch... the biggest one is Windows-only applications. For a lot of people who might be inclined to switch, these applications are usually confined to games, like Fyron and Arkcon have said. But sometimes its because certain alternatives to the major Windows applications are found to be lacking in some way. Personally, the only things keeping me from switching over are Photoshop and Trillian (and I think iTunes is OSX/Windows only, so now that I have an iPod, that's holding me back too). There are alternatives to both Photoshop (the GIMP) and Trillian (gAim, Miranda), but I'm not as familiar with them. Maybe over next summer if I play around with them and find all the features I use in the Windows software in the Linux software (and find a way to get iTunes/iPod to work in Linux), I'll switch. But for now, I get W2KPro for free from school, and things are working for me, so no need to switch.
And about your explorer crash problems... if you get dumped to a no-interface blank screen, hit Ctrl-Alt-Del, and open up the task manager. Go to the Applications tab, and hit the New Task... button. Type in 'explorer' and hit enter, and voila, you should have the interface back.
And if you don't want to go through re-installing everything because of explorer crashes, try experimenting with an alternate shell. I used LiteStep for a while (before UPS mangled my computer... long story). Only reason I didn't install it again is because I didn't back up all the tweaks I made to the skin I was using, and I didn't want to have to re-create everything. Plus it confused the hell out of a lot of friends who get upset when they don't see the friendly 'e' Internet Exploder icon
It will completely go around explorer, so if that is the root cause of all the problems, you can just kill it completely and use the new shell. Google for information on getting/setting it up, and ask for help here if you need it.