If fusion is able to run dragon age on a system similar to yours, I would say get the orange box. It's 5 games in one package and they're all very great quality. It includes Half-life 2, Half-life 2:episode 1, Half-life 2:episode 2, Portal, and Team Fortress 2. Each one of those games is of the same quality as a full priced game, but you get all of them for the price of one. They're all FPS games; portal is puzzle game, the half-life games are GREAT single player games with a wonderful story and TF2 is an online multiplayer game with a very active community.
Totally with you. Its an excellent deal, 5 brilliant games for £15, perhaps even £10 in some places now. And it has a low spec requirement, I'd really recommend getting it.