today's space sims?
what was the last space sim to even come out? Darkstar One?

I agree, the Freespace games really are a class of their own. I still remember the first time I played it, the tutorial was great and the music, the graphics and the design made me feel very alone and vulnerable in my little space ship and I really wanted to learn how to fly this thing, just to survive this empty space. And then the Shivans appear, and survival becomes the only thing that actually matters at all.
Amazing game :-)
As for today's space sims .. well, the X series is the only one that comes to mind. I haven't played Darkstar (but haven't heard negative things about it either), but it seems kind of arcade to me (which I don't like, it's called space *sim* after all).
X³ on the other hand is a really *deep* simulation which can cost you weeks of your life.. which is great if you're into this kind of games, but I think it puts the game in a whole different league than Freespace.. which leaves the latter as the last game standing ;-)