I've had FireFox eat my bookmarks more times than I care to count.

I have worked part time for a security company that dealt in cleaning up infected computers. I've seen many infections with FireFox installed and set as the default browser. I can't say that I've seen more as more people use Internet Explorer.

Before anyone quotes and says that FireFox is more secure than IE make sure you include links so that I can go test it myself and get infected "just by visiting" a website.

You can drive a VW and a Geo Metro off a cliff, and neither one is going to work worth a crap afterwards. Treat your browser nice, stay off the inappropriate sites, know what you're doing, and you'll be fine.