Well you should really always have both on the system. I think Firefox is def. the best for a explorer alternative. But have you checked out 7.00 it has allot of Firefox's features such as tabs. Overall I use Firefox the most as it seems to be better for use with my firewall (Zone alarm). Always have both is my advice.
mozilla is the best. there si 100000000000000000000 plugins which are not in internet explorer. but in internet explorer 7 perhaps there is some plugins.
Yep there are loads of fantastic plugins for Firefox. Save all is my fav. you can save all images on a page at once which is great for large galleries.
Check them out at; https://pfs.mozilla.org/plugins/
Gonna have to wait a bit and see how Explorer 7.00 shapes up its still at a beta stage. At the mo I think Firefox wins for the majority of browsing.
Firefox for me runs so much faster than IE. Though I do use both, seeing as some things on the web dont run on Firefox, therefore handy old IE is always there to help.