Have a look at this game called infinity. The dev blog there is worth a read, full of intresting information!. The game is still in development and is ment to be some sort of mmorpg.
I've been keeping a close eye to Infinity for some time now. It takes the Newtonian approach of Elite II Frontier, but tries not to repeat its mistakes. I-War 2 and Terminus are good examples showing that there are ways to do realistic space simulations that are fun to play.
If you're into hardcore space games, I also recommend you to take a look at Vega Strike, which is an open-source Frontier-like game. It's still in progress, but it has been playable for years now.
Also, if you don't mind a top-down approach in space games, click on my signature link ;)