Texture resolution is always going to be better on PC but I do agree that same games on console do look really good, far better than you would expect them too look. Most of them are PS3 games to be fair, like Killzone 3, Uncharted 3. Crysis 2 looks decent.
Graphics on Forza 4 and GT5 are really impressive, I think that is in part due to the fact that no one seems happy to do a large budget AAA racer for the PC on the scale of the Forza and Gran Turismo games. I dream of the day when a good PC dev announces a huge pc only, or atleast PC lead development, large scale racer. The kind with hundreds of cars, tracks, modifications etc.
I remember when the guy that makes Gran Turismo 5 commented that he would like to of put a free roam mode in a large environment in GT5, but couldn't because the PS3 doesn't have the power to render large detailed environments while using the same car models and lighting techniques as the rest of the game on normal race tracks. Like holy ****, that sounds awesome, do it on PC ! I'd do so much for a semi realistic racing game in a huge open environement, but no one has done it.
Fortunately, I quite enjoy GTA4s driving mechanics, so that has partly met my desire. But it's hardly realistic with nice car genuine car models and the like.