I'm just wondering, since firefox/iceweasel seems to be getting unusable. I have a 2.2GHz C2D box with an nvidia card at home, and a 3.0GHz C2D with a (lame) ATI card at work. I find that firefox (or xulrunner-stub) have memory leaks, and after a couple of days, it eats up a significant amount (10-30%) of memory. The work box has 3GB and the home box has 4GB. It also eats up a significant amount of CPU.
This morning, after idling all weekend, iceweasel on my work system was chewing up between 70 and 100% of my cpus, and scrolling pages were hesitating for several seconds. So what do others use? --b