I'm a Firefox user -- the only time I use IE is to test webapps at work. It's a lot easier to lose a customer than get them back, and Microsoft lost me to Mozilla sometime around late IE4. Then, once it became obvious that mozilla.org was going to concentrate on Firefox and ignore the Mozilla browser, I switched again. My boss (a Mac guy) is quite fond of Safari, but unless/until Firefox goes down some stupid path that drives me away, I'll stick with them.

Those having problems using IE may benefit from trying a different Web browser -- I always install multiple browsers for troubleshooting. If a problem is common to multiple browsers, then it's something else (perhaps a Web site's CSS or page scripting), but if it's browser-specific I can search for browser configuration issues (it may still be CSS or scripting, but a different subset of browser-specific issues). I also test from multiple computers, which can help spot whether it's computer-specific, or an issue related to the browser patch/version.

From my work, both IE (v 8.0.6001.18702) and Firefox (v 3.5.2) running on WinXP Pro (SP3) work fine right now.