I just bought Tomb Raider for the 360 (waiting for it to install on my hard drive right now) and I expect it to look surprisingly close to the PC version (obviously there will still be a noticeable difference though) because I have my 360 hooked up to a HD computer monitor that makes games look literally two times better than on a normal high-end HDTV. Computer monitors are a big part of why PC games look so much better than console games.
Can't wait to play it!