Mythbusters beat "unbreakable" fingerprint door lock shows how biometric security can be broken, and fairly easily it seems. The point is that biometrics is not authentication, as authentication requires a 'secret' of some kind. Anything you leave behind (such as a fingerprint) can never be secret. I mean, didn't anyone out there watch Gattaca?
I've seen a lot of smallish Notebooks out on the market these days that are touting biometric security. I'd be ok with using my fingerprint as a substitute for my login name, but I think I'll stick with entering a password manually thank you very much.