FF3 - can't beat the extensions
Only thing I'm interested with in Chrome is its implementation of multiple threads/processes to improve performance/stability.
That being said, its not enough as-is in its current beta form to replace FF, and once FF and the other browsers inevitably follow suit in implementing their own version there could be even less reason to go with Chrome.
Right now I'm currently using it out of novelty - I don't mind beta testing new browsers, its how I got into Firefox back before it was even called that (previously known as Phoenix/Firebird)
Anyways, competition is great, better browsers for all!