Single player games - MEEOYO

While browsing EuroGamer I stumbled upon this great comment:

Hooray for single player games (Or "massively engrossing experiences on your own" MEEOYO)

Exactly my kind of game. To me, the idea of massive online gaming seemed like heaven, but practice has shown that online games often lack immersion and are simple an alternate version of real-life rather than a fun, engrossing world to play in.
But these days it's hard to find a quality single-player game. So a couple of weeks ago I got FreeLancer. A sort of Elite-clone/Privateer-sequel. Wonderful graphics, great gameplay, amazing immersion and nice storyline. Great except for one thing: after finishing the story, there is absolutely nothing to do. The game-designers created a giant universe, only to have you follow a predetermined story, or fly around shooting stuff.

So now I'm looking forward to X2. Totally freeform gameplay in a giant, dynamic galaxy with fun things to do.
I'm getting a fancy pixelshader videocard for Thief III / Deus Ex 2 anyway. This should be a fun investment :).