EVE Online is an MMORPG set in space. It has very good graphics and a fairy complex game system. With a wealth of options and things to do, it would almost be the perfect game except for the minor issue of cost, at whopping € 14.95 per month. There is however a 14 day free trial and this should be enough to convince you that it is well worth the cost.
The graphics are stunning, needing a big-ish screen to fully appreciate them. The title easily competes with other titles like World of Warcraft and Warhammer online.
The game runs on Windows and Mac OSX with complete compatibility.
Here are some screenshots (These screenshots were taken from the official EVE website):
