Depends on the genre. Playing punk/metal/faster music just screams for a pick IMO, even though I know a lot of guys use their fingers. You can't get clanky tone without it and that's the sound I like for certain bands I've been in.
On the other side, I've been in lots of other kinds of bands, I would never play any other genre with a pick. Even when I'm doing sludge and stuff I use fingers. Clanky tone doesn't work in every situation.