The 360 has a VGA adapater, so you can plug it directly into your monitor, a much, much better solution then trying to run it through the ATI All in Wonder, and having it upconvert the 360's resolution to your monitor. I'd bet you'd experience some delay that way too.
I have an ATI All in Wonder, as it was the best deal at Newegg at the time for my video card, and I've never been impressed with the video functions at all. If its a good deal, by all means, but the "Wonder" part is pretty blah.http://www.ebgames.com/ebx/product/258837.asp
Works very well to my Dell 2005, and lets you select from a lot of resolutions. I'd definitely recommend it.