I've yet to upgrade to Firefox 2, but here is an interesting thing I've noted regarding Conquer Club and Firefox (1.5.0.9).
With regards to CC scripts, I have the Dice Analyzer as well as the Greasemonkey script. (Also have an RSS feed, but I doubt thats doing what I'm concerned with). I also have a program up to monitor my RAM usage (not a Firefox extension).
As I play my rounds in CC, I've noticed that, for each attack I do, my free RAM total goes down 1 or 2 MB. This was especially noticable in my World 2.0 games, where I'd start a round in a game with somewhere around 170 MB free and would end with something around 10-20 (though I even was forced to clear out my RAM for a few rounds due to the number of attacks needed).
Given that this happens with each attack, I'm assuming this is connected to the Dice Analyzer (as it would be collecting dice data per each attack, right?). Has anyone else noticed this kind of behavior? CC is the only site that I visit that causes my RAM to jump, and I'm assuming its from some extension installed.