I'm really into Denny's Favorite, Wyeast 1450 I believe. It says:
This terrific all-round yeast can be used for almost any style beer and is a mainstay of Denny Conn. It is unique in that it produces a big mouthfeel and helps accentuate the malt, caramel, or fruit character of a beer without being sweet or under-attenuated.
I read somewhere that it gives your beer a "luscious mouthfeel", and I really agree with that.
Otherwise, I'm a fan of Wyeast 1056, or White Labs 001 for all of my American style beers.