1680x1050 is not supported by the 360 VGA cable. you'll have black bars on the top and bottom of your screen. currently Microsoft doesn't support 1680x1050.
lame. i dont mind having the black bars there, as long as i dont get a stretched image, im happy. ill get a KVM switch, that way i can switch between 360 and PC on the same screen with ease ^^
I was planning on eventually getting a VGA cord but this is kind of a deal breaker with my monitor. Hopefully there will be future support but don't count on it. My only other though about a setup like this is, what to use for sound. I use standard TV speakers and I'm not sure how else to get sound as all my PC stuff is 3.5mm .