A: Lots. But after trying out Firefox 2.0, you wouldn't want to use anything else, would you?
IE 7 - now features tabs and integrated RSS feed reader
Opera 9.1 - free to try; $29 to buy
Lynx - text browser
Konqueror - only heard about it, know nothing about it
Safari - default browser on Mac OS X
iCab - for the Apple Macintosh