Firefox tends to be a memory hog, Opera is a good one to try out - that said I use Firefox. If you're on a MAC you can get Firefox, but Safari tends to be a better choice. Or you can buck it up and run Linux, no worries about virus and crap. If anyone is interested I'd be happy to help set up a Linux box - I run Ubuntu, but SUSE is a good one also. Actually, I've got an old PC with Ubuntu loaded, and a monitor if someone would want to trade a Monarch or ROC (or any other good beginner disc). It's a Pentium III, and I think only 512 RAM, probably only a 20 or 30 gb HDD, but it runs Linux fine. It's not worth much, and it's just taking up space in my closet, so I'd trade for a disc... Anyway, IE is a POS, hands down worst browser in my book; besides being a memory hog it's unstable and code bloated. A quick Google search will show there are several browsers out there, some more lightweight than others, but if you've got enough memory on your box you pretty much can't go wrong with Firefox. Not to mention is has a number of add-ons (I like Foxmarks) that make it pretty customisable and user friendly.
Just my two cents,