Trine 2 is a puzzle platformer that can be played in Co-Op for up to 3 people, the game does render correctly to horizontal plus but unfortunately the menu, HUD and cutscreens are all stretched. I have an extended version but that won't be ready till tomorrow. Once again if your monitors width is larger than 1920 pixels and you have lots of bandwidth, set the quality to original and play the video in full screen for a much higher quality.

Video Link: Trine 2 (Triple Monitors / Eyefinity / Surround) [~4K]
Forum Thread: Trine 2 (Triple Monitors / Eyefinity / Surround) [~4K] Video

Tom's Hardware has published their latest iteration of Best Graphics Cards For The Money, so if your in the market for an upgrade, and have a fair idea of what your budget is, you should check this article out.

Best Graphics Cards For The Money: December 2011