Only one good answer - It has its own directory for cookies also so you can open one account in IE and one in FF - The only thing to watch for is the pop up question as to which will be the default browser. Make the selection as to the one you want and then select not to ask anymore. If you goof and pick the wrong one you can undo it in the options menu.
well Firefox if you want an all around good web browser, however Flock and SeaMonkey are pretty good too. Mosaic is good as long as you don't go to sites that have a lot of HTML. Pretty much anything other than Internet Explorer is good (even NetCaptor, but just barely good for NetCaptor).
Opera
Safari
Maxthon
Avant Browser
Advanced Browser
Ace Explorer
Lively Browser
TheWorld Browser
Element Browser
Polstergeist Browser
JamesZhu Internet Browser
Runecats Explorer
... and there are more.
With so many variations ... I still think you'll most likely prefer FireFox as an IE alternative.