I am an eternal fan of Evochron. I had all of the versions and its still on my backup/previous computer. It was my space sim before ED. Before that I played Independence War(s), Freelancer and Freespace II. The Evochron founder is awesome, its basically a one man project, especially in the later versions. GL HFSteam sales are evil things.
I've splashed about £50 or so thus far I think, and it's still got another two weeks to run.
Some of the games I've picked up are:
Evochron Legacy, because it intrigues me. A Newtonian based space sim with elements from Elite. Played the 'shooter on rails' version with Mercenary, but this is a whole other level.
while True: learn() which appeals to my (not so) inner geek.
Weedcraft Inc: because, why not?
There's more, and there probably will be more yet. Like I said, evil things...