As soon as I read this thread, I ran into this at lifehacker.com http://lifehacker.com/5246101/firefox-optimized-build-runs-faster-uses-less-memory Firefox 3.5 Beta 4 Optimized Build
Had Chrome, wasn't feeling it. I like Opera much better than Chrome... but Firefox is still my browser of choice. In regards to Firefox, try disabling the pre-caching feature. http://fairlyrealistic.com/2006/02/26/mozillafirefox-using-too-much-memory/
What kind of "video" are you watching so often? You seem very adamant about removing it from your browser..........
FYI: I removed unused add-ons and themes, and now FireFox is running like a charm. TRY REMOVING all the ADD-ONS you DO NOT use. It worked for me and now it works better.
