My IBM Thinkpad runs Halo pretty smoothly at 1024x768, although the video card doesn't support some of the nicer effects in the game so I dunno if you want to count that as cheating or not Mine's one of the lower spec Thinkpads anway, and seems to be around £1000 ($1400?) when I looked it up on their site (since I got mine free )

My brother has a widescreen Dell, and there doesn't seem to be any compatibility issues with it. And that CAN run Halo with all the full graphic effects unlike mine. It also has pretty darn good built in stereo speakers unlike most laptops where they'd otherwise sound tinny or flat or whatever.