Sony can brag about graphics until aliens come and take over the world, unless the devs make use of these graphics, Sony can't do much, its like how Micro bragged about gfx with the xbox original, but yet devs didn't make much use of it except the odd few, which was a shame cos it had so much potential. At the end of the day, the more variety and games you have with good gameplay, is the more success you have. Sony's lackluster line up may not touch 360's best offers, but take into account, it is but a launch line up, not the best PS3 has to offer by far, we won't know until we are at least a year to two years in of what PS3's middle range graphic games will look like, but if the launch is being compared to 360, thats laughable already.
None of the launch games have used the PS3's best potentials, in fact, the devs were the first few to make use of the PS3, therefore both new and unexplored, they could only do so much, plus the rush for release and the lack of knowledge of the online Sony had up thier sleeves, they're bound to be nowhere near as good as 360 2nd gen games, but yet, they still manage to do just that because everyone is comparing them. Sony is capable of overkilling with thier own game Killzone 2, as it is thier console, and thier game, but lets see how that turns out, another hyped franchise, hope the hype is worth it.
But compared to what 360 gave us at launch, I think the line up for PS3 is damn impressive if you pretend 360 wasn't there. Its not bad at all, most games scoring no less then 7 at most sites, thats pretty darn superb.
But like JToTheP said, despite Sony's ability to talk the talk, none of thier launches have ever had a graphically superior title, all the starters are usually kinda bland and limited, the potetial doesnt come out untill at least a year od so into its life cycle.