It seems to me that one of the very best facets of xbox 360 is that it has allowed gamers to play console comfortable versions of the best pc games of its time that are much closer to the pc versions in terms of graphics, etc, than any other console ever has before.  In fact some of the biggest games on the 360 have been the biggest pc titles like Fallout 3, Bioshock, and The Call of Duty series that the 360 has been able to play just as well as the pc.  I would say that both pc gaming and the 360 have benefited greatly from this relationship.

     However, pc power increases dramatically every eighteen months, and I know that we are all familiar with the idea that the only way to keep up with the latest and best pc games is to replace our very expensive pcs every two to three years or otherwise just have to be content with not being able to play the latest and greatest pc games.

     I don't think we are willing to trade in our consoles every eighteen months in a similar fashion.  So, I am wondering how long can the 360 keep up with the latest trends in pc gaming.  Even an enhanced 360 would eventually run into the problem that pc games were performing miles beyond what it was capable of in the not too distant future.

     So how long to you think the 360 or 360+ could keep up and deliver the best console games versions of pc games with no noticeable differences to what is in the pc games as the current 360 does with Call of Duty, Fallout 3, and Bioshock.  How important do you think having the best console versions of pc games is to the xbox, and how long do you think it would be before the differences in next gen pc games and what the 360 or an enhanced 360 would grow so large that Microsoft would have to release a new more powerful console to deliver these games in home console format in an acceptable fashion? 

Eh? I don't see how PC gaming has ANYTHING to do with the xbox or the release of the next xbox.

Please explain.

When you look at screenshots, it can look as if the 360 is still on par with modern PCs.

When you take into account framerates, resolution etc. modern PCs are quite above already.

           ^^ This

           Crysis 2 has been confirmed for PC, 360 & PS3.  So......we will have to wait and see if the comparisons are extreme, or if (unfortunately) we recieve a extremely graphical dumbed down version on console in comparison to PC. 

Or another possibility, if the PC version is dumbed down so that they can make it similar between all platforms (excluding resolution and framerate which are never limited on the PC).

To answer the OP better, besides powerful hardware on the 360 and PS3 there are two more reasons why games look close:

1- Modern game development is so expensive that PC developers also make console games now. This didn't happen so much before.

2- As graphics gets better, it gets harder and harder for gamers to tell the difference. There are many games nowadays which have no big difference between each other. Hence the wars of "Forza 3 vs GT5 graphics", when they look pretty close.

For those reasons, it's pretty possible that most people won't see a big difference between PS360 and PC games for a long time (again, excluding resolution and framerate).

"Eh? I don't see how PC gaming has ANYTHING to do with the xbox or the release of the next xbox.

"Please explain. "

Considering that throughout the history of the xbox and 360 both xbox biggest games have been traditional pc type games including first person shooters like Halo, The Orange Box, Call of Duty, Bioshock and western rpgs like Morrowind, Kotor, Oblivion, and Fallout 3 many of which either started first on pc or released at the same time on pc and xbox, I don't see how anyone can't draw a connection between pc and xbox games. And part of the appeal of the xbox and especially the 360 is that you can play many of these games on the 360 in a close enough fashion to their pc counterparts to satisfy many gamers.

If there was a huge gap in the performance of these games on pc and 360, then I don't think so many people would be buying them on 360 and that would take away a significant part of the 360's appeal.

yes and consoles are heavily advratised, more than pc games.