Hmm, the only gripe i have with it currently is the download manager
Yeah, that sucks, and hasn't gotten any better. What bugs me is that the download manager will pop-up when I save images from pages, which doesn't make sense since the files are already local, and it will NOT always close when downloads have finished, even when you have that option explicitly selected. The best you can do is disable the feature to automaticly show the download manager when starting a download. I have the "downloads" button next to my address bar, since they changed all the hotkeys in 9.3, too. I sure hope that since Firefox has gone to 1.0, they will stop moving everything around.
That's on Windows, though, on Linux it's another matter. I get random crashes, mostly caused by flash pages (evil, i tell thee) and java.
Really? Flash hasn't given me any trouble on either Windows or Linux. Try downloading the latest player from Macromedia as a stand-alone, instead of using the .XPI auto-installer.
Flash is a major CPU hog, though. DON'T view more than one Flash page at a time or your browser probably will lock up. This is true on all browsers, I've found.
As for Java, well, 1.4.2_05 has proven to have quite a few bugs. I have IE set up to use the MS Virtual Machine and Firefox with Sun Java. Both Java engines cause lots of problems. I don't know why people like Java so much.