On a full HD TV or high res monitor a "high spec" PC will obviousely win. On an average Plasma or LCD TV (1024x768 / 1360x768) there is very little difference. I play my 360 and PS3 on the TV and PC on a monitor at 1680x1050.
In all honesty I prefer consoles for sports and fighting games, with PC's being better for FPS and strategy. Although saying that, the PS3 is not far away from the PC because you can connect a mouse and keyboard to play some FPS games.
The problem with PC's is that in 12-24months time current hardware will struggle to play games. The 360 and PS3 will be fine for another 5 years because game developers will get better at there job (developing), rather than relying on hardware boosts.
Has nobody heard, PC gaming is supposed to be dieing out

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edited to add COD4 is way better on my PS3 than it is on the PC. That's because I play it on my plasma, with full surround sound. Graphics may not be quite as good as the PC (8800GT / 3.3GHz C2D), but the all round experience wins easily. Each to his own I guess.