Most of the games look really similar with small differences here and there with lighting and blurriness or edges or whatnot, but it looks like Bethesda was the only company to actually put effort into making their game release on the PS3 that was a year later actually look signifcantly better.

Here's a feature that Gamespot do often comparing 360 and PS3 multiplat games' graphics:

http://www.gamespot.com/features/6171831/p-5.html

Oblivion was the only one that looked better on PS3 significantly (as in more than what you notice by looking really closely) 

It may look better on the PS3 but the only system it's worth playing is the PC. Oblivion isn't a bad game, but the only way to make it actually good is to use user created content.

 Wrong! It's very good on consoles too and i played the PC version. There is so much to do in it...

hmmm... wouldn't say significantly better.  it does have better details for the character close-up shot, but i like the shades and what-nots on the 360 version better.  i'd rather have high frame rates than intricate details.

 Wrong!  It is a good game with lots to do but it also has very many flaws.  Just a few off the top of my head (it's been more than a year since I played so can't remember everything) would be the horrible menus, the bad maps, and the broken leveling/skills.  You cannot fix those things on the 360 and PS3 version because you cannot download the user created mods.

I read the Yahoo games review of Rainbow Six Vegas (PS3) recently, and they seemed to indicate that some bits of the game looked better. I know that's in contrast to what the videos from game trailers suggest, but we'll see when we get the final copy

Also there was that horrible bug in the PC version where nobody was naked. Luckily that was fixed with a user-created mod. And then it got an M rating, but whatever.

 The leveling system is made that way for a reason and I like it, you can go wherever you want and create your own story instead of being constricted to certain areas for certain levels like most RPGs. The maps, menus are both matters of strict opinion and minor issues.

So bad maps and menus make a game not good? Anyway your opinion, don't try to convince me Oblivion is not good on consoles because I know it is :)

The flaw I was referring to in the leveling system is that you can't beat the game on the hardest setting if you don't level your character perfectly or near perfectly. That goes against your idea of doing whatever you want.