I normally use two browsers, Chrome and Firefox, so I can have two Gmail accounts up and running, but the newest Firefox 7 has been running just incredibly slowly. Even if it's the only program going, it regularly hangs on random websites, claiming an unresponsive script (which work fine on Chrome), crashes a lot, seems unable to handle more than 5-6 tabs, and generally runs like shit. I have a brand-new laptop, not the most expensive (obviously), but it's got 4 gigs of RAM and a quad-core processor, so it should definitely be able to handle a single web browser. I've tried all manner of fixes, and reinstalled several times, but nothing seems to work. Besides, Chrome runs great, even with more than 20 tabs open.
I've got an irrational aversion to Internet Explorer, so I've installed Opera. I'll let you know how it goes.