Best, Visually on the Playstation right now is probably Uncharted: Drakes Fortune. Certain portions of that game had me wishing I didn't have bullets flying by my head so I could take it in more. Heavenly Sword, while a good game, always seemed more of a God of War game to me, don't get me wrong, it's good but I couldn't help sitting there thinking "wow, that's similar".
Resistance is a great game as well, the only thing that keeps me from getting it is the fact that it's still at full asking price even though it was one of the PS3's initial launches. Resistance 2 has been slated for sometime in 2008 so I plan on waiting until that comes out, the initial one has a price drop and pick them both up at the same time.
Might not be up your alley but I'd look into Call of Duty 4 as well. First Person Shooter, great online, graphics are very, very good as well.
But those are the big sellers with decent graphics. Only other ones I've really heard about that will be visually and game play good are a few of the new major titles planned for April or beyond