So it seems like I'm not the only one who has this problem. I have Google Reader open all day in one of my firefox tabs, but it's causing firefox to crash all day long, with the very informative "illegal operation" error. Thank goodness for firefox's little "restore your previous open tabs" feature, otherwise I would of moved to another browser by now.
Firefox is on thin ice actually. Apart from the random crashing (which I can deal with), it also seems to eat up system memory like crazy and the newer versions of firefox haven't really resolved this problem, which tons of people seem to be having.
Currently, I have 6 tabs open, Gmail, Blogger CP, Design-feed, Google Reader, a page with google search results and a random html website. Firefox is using 84mb of my precious ram. If I add another site to the list, this time a full on flash site, it jumps to 110mb. Crazy really, but it seems there isn't much you can do about it.
Yes I have tried Opera, but that too has its own flaws, like randomly refreshing the page before its fully loaded and seemingly limiting you to the amount of flash sites open in tabs you can run simultaneously.
I'm hoping the guys at GReader will sort out this crashing issue, they seem to be working on the site all the time which is refreshing to see. If anyone has any temporary fix's for the crashing problem (or the firefox memory leak) I'd love to hear them!