The graphics of most PS3 exclusives are beyond what the X360 can churn out. Examples: Uncharted 2, God of War 3.

There's also a recent comparison video on ME2 which shows markedly better graphics on the upcoming PS3 version.

This isn't unexpected as the PS3 has superior hardware overall, unfortunately that hardware is also vastly more difficult to develop on than the 360. For multiplatform releases there's often little difference, and some games look better on the 360 due to the PS3 version either being a shoddy port or the developers falling short of the mark in utilizing all the computing power.

Platform exclusives usually have the best graphics regardless of platform just because they have a far tighter scope to work with

Uncharted 2 is visually stunning though.

The bits without Elena or Chloe are good too

With over a year of extra polish i'm not suprised.

The hardware isn't as good as sony claimed never has been the original plan was to use cells for everything about 2 months before they completed planning they realised this wouldn't work so a 7800GS* was leveraged into it for the graphics.
Now the 7800GS was a good bit of tech but it lacked the memory unification that a good console graphics chip needs added to it.

Now it can theoretically kill the Xenos but a lack of memory to handle textures means they work at about the same speed. Most of the other graphics advantages that people complain both render games at 720p in most cases (theres 2-3 games on the ps3 that are true 1080p but theres waaay more that render at something like 572 and no thats not due to xbox ports its due to cell)

So yes you may get the occasional PS3 that leverages Brays ability to store higher textures but most don't (thanks to the ps jailbreak we now know the average game size is 8GB once you remove redundant data repetition) so yeah graphics wise they're about the same.

*interestingly the Nvidia graphics is the most likely reason the price has never dropped as much as expected they refuse to license their tech so Sony has to buy the chip from them no matter what MS can shop their processor around and get better prices (both the Xbox and Kinect make a profit on each console now sony is still a loss leader)

This is the point exactly. The design of the PS3 was to promote streaming uncompressed high resolution textures directly from the blu-ray disc, therefore alleviating the need to have as much video memory as the 360 does. Then the graphics chip is free to do anything else but handle textures; and some of the more processing-heavy operations should be "outsourced" to a cell.

Unfortunately, few games fully exploit these techniques as they're more costly to develop for. For multi-platform releases developers are often too lazy or time-constrained to do it; which leaves you with only a handfull of exclusives that really utilize the full power of the console.

Although we've seen a few more examples of cross-platform games being properly adjusted to the PS3 lately; Mass Effect 2 is a good example.

Or it could be the fact it more than quadruples the arts cost seriously the cost of doing it that way is not worth it for the minimal graphics improvement the way you say it makes it seem that developers sit on their ass all day -.-

if you have a PS3 then you absolutely MUST get Joe Danger from PSN

This is probably one of the best exclusive PSN games - I think I had the most fun with this title than any other one