its standard on my PC anwyay, most of my games run at max spec.

No, there are plenty of games which render in much lower resolutions.

What's your PC configuration? What kind of framerate do you get when running the game in 1920 x 1080 with maximum settings?

Nomatter if you get a good perfomance out of your beefy PC, it may well be that there will be a game the next couple of years which will make your system crawl even in lower resolutions. For instance if you a PC in 1996 which could play Quake well enough, then a year down the road a new game comes along which suddenly stutters and looked like shit on minimal settings.

On consoles it's more like the opposite is true, newer games in general will make much better use of the hardware resulting in far more impressive and much better performing games around the end of the console's lifecycle than in comparison to the early games.

I just looked it up, gt5p is 1280x1080. That's not 1080p.

It is, 1080 lines progressively scanned. It's not FullHD, but a much higher resolution than 720p rendering such games on the PS3 this will be scaled up to FullHD output. You have different widescreen and square 480p (again meaning 480 lines progressively scanned) resolutions (amongst other 480p resolutions) as well.

But they don't call it 480p if it's running a 4:3 pixel ratio upscaled to fit a 16:9 format, which essentially is what GT5:P is doing in "1080p".

When? With Nintendo's next console.

It may or may not be the standard in the next generation depending on when the next generation starts but it will certainly be the standard for the following generation. It all comes down to trying to balance a bunch of demands on processing power and resolution tends to lose out mainly because it is not noticed all that much. Personally, I have always reduced my resolution from 1600x1200 to 1280x1024 and then to 1024x768 before I begin to reduce effects in PC games; I have (typically) found that it is difficult to see much of a difference between 1024x768 with 4xAA and 4xAF and 1600x1200 with  16xAA and 16xAF while playing the game (there is a huge difference while watching videos or looking at still images though, but I find I am typically distracted in gameplay).

The game is horizontally scaled to fit FullHD displays, like the HDV 1080i standard uses a 1440 x 1080 resolution and is scaled up to 1920 x 1080 on 1080i or FullHD displays.

For the human eye the vertical resolution is more important. Scaling algorithmic processing can enhance image quality so for example 480p content may well actually look better on a HDTV than on a 480p native display. For example Toshiba uses a simplified low en Cell-derivative to enhance the quality of DVD output on HDTVs.

IMO that would generally be overkill for most PC gamers. The average PC monitor is much smaller than the average HDTV, actaully I prefer a small 17 inch (sqaure) LCD on my desk. A big screen is much more suitable for my living room. 1024 x 768 is perfectly suitable for games on a 17 inch screen.