It seems your experiencing one of firefox's main flaws of being a memory hog, but yeah don't move back to IE. Okay well before you are allowed to complain about firefox you first must make sure you are running the latest version which is 1.0.7 to find out what version you are using go to Help>About Mozilla Firefox. If you running anything less than 1.0.7 you are not allowed to complain. Then after you update your going to want to be sure you clean out your Cache (any browser can get hosed up by too much stuff in its cache). Go into the options then go into privace then go to cache and hit clear.

To help with firefox being such a memory hog your going to want to change that cache setting from the default 50000 KB to something more reasonable like 10000 should be fine expecially with a high speed connection.

That should help you with your problems I hope. If not the Opera browser has recently decided to take out there ad on the unpaid version so now it's completly free. Thats another good browser http://www.opera.com But I stick with firefox And don't use the avant browser because that's just IE with some bells and whistles but it still has all the security flaws as IE.