Yeah, I don't like it when people say "OMFG FIREFOX IS TEH UBER SECURE!!!1!!11" or something similar
. FF is no more or less secure then IE is, it's just that IE is by far the more popular browser so many more attacks are directed towards it. But now that Firefox has picked up a lot of steam, there'll be more and more attacks towards FF, as well as spyware.
Personally, I use it for the extensions. You can do almost anything you want with them, and I can't surf without it now. Same with tabbed browsing