It seems to me there are 4 options if you want a decent PC + X360 set up with a big screen:
1. Get the BenQ FP241W and tolerate the 11% vertical stretch on the 360 (probably not that noticeable unless you're looking for it).
2. Get the Dell 2407FPW and put up with its niggles (poor component inputs, some problems with tearing using the 360 over VGA in certain scaling modes, minor banding, lack of 1080p support over DVI)
3. Get a HDTV for your 360 (the new 23-26" R7 series Samsungs can be had for under £500) and enjoy 1:1 pixel mapping at the native res of the screen. This is always going to be the best option if you have room.
4. Wait indefinitely for the perfect all-in-one PC screen