I hate it when I click the wrong button and wipe out my damned post. Anyway, FF is a striped down version of Mozilla, as Ragnarok said. Not sure what he meant by the "spyware" comment, but FF is just the browser engine. Mozilla also includes a chat client, an email client, and a news reader, if you like. They are both very secure (especially compared to IE; just read the news on the Download.Ject/Scop trojan).
I must be cursed, because I haven't had tons of luck with FF 0.9. I've had to uninstall and reinstall twice at work. Meanwhile, I've been running 0.8 here at home without a problem. I think out of the box, 0.9 is probably fine, but I run a lot of plugins, and some of the plugins don't like each other on 0.9. The best thing about FF is the expandability. Mozilla supports a fair number of plugins, but most of the communities effort is towards FF these days. In fact, after 1.8, I'm not sure if there will be any further work on Mozilla. The number of plugins for FF is mind boggling. There's zoom image, undo close last tab, dictionary search, Sage (an RSS aggregator/sidebar), blogging software, web editing software, calculators, tetris, etc. Moz and FF have THE best built-in pop-up blocker on the planet, and it's free and constantly improving. There's even a plugin for removing any object from a webpage. So I could right-click on an annoying flash ad on IGN and block it.
Mozilla and FF store your bookmarks in a single file called bookmarks.html which is stored in your C

Documents And Settings\[username]\Application Data\Mozilla (or Firefox or Phoenix (FF's old name). If you back up that folder, it will save your bookmarks, passwords, cookies, preferences, you name it.
I'd at least give FF 0.9 a try, since it's a small download and it won't fry your system or anything. Once you start using tabbed browsing, you won't be able to live without it.
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