Firefox sometimes gets a wrap of being a memory hog. It isn’t perfect, but I normally find that the issue is to do with a add-on or three that I have installed.
If I start to complain about Firefox, I try to disable all plugins for awhile to make sure that I am not moaning about the wrong person.
I have been pushing the poor browser a long way recently. I don’t think that current browsers were quite designed for 4 windows of 20 tabs each containing rich applications such as Gmail, Pipes, and Picnik all going at once.
I found that over time my memory was slowly getting used, and Firefox would slow down to a crawl.
Firebug seemed to be one of the culprits in my case. When I had it disabled the memory footprint went down and has been stable.
Obviously, I can’t live without Firebug. There are a lot of add-ons that I do not need on all the time, but that I want available.
Ideally, I would be able to dynamically load and unload add-ons. It would even be nice to customize windows so window one is “pure simple browsing” and has nothing on. Window two is dev window and has everything tricked out.
As we push more and more into the browser, it will become more of a container that I need to plug items in and out of on demand.