Which space sim should I get?

x3 is too bugged 
sins is a RTS 
freespace 1 + 2 are some of the best space sims ever created (make sure to use the open source graphics mods etc)
 
eve online is the best and biggest space sim and cheap to play if you use the "buddy reward scheme and buy accounts cheap via steam"

Are you familiar with the Homeworld series?  The original game is a free download if you are interested.  See here.  Not piracy it seems.  It's also available on CNET.com.

I have Sins and Homeworld 2, and I can say that Sins is more of a 4x type of game, and it'll take you at least 2hrs on even the smallest map.  It's a great game, though, if  you have the time for it. HW2 will allow for quicker games, but lacks the depth that Sins will give you.

Dont forget Gal Civ 2, its turn based instead of RTS but it's probably the best space/galaxy conquering sim out there.

Be a bloody man and get X3 , not some hollywood shit. 
 
Ok ok , if its between those two it depends. Honestly though, Sins of a Solar Empire is better value. Freespace 1 and 2 will always be dirt cheap.

" Dont forget Gal Civ 2, its turn based instead of RTS but it's probably the best space/galaxy conquering sim out there. "

Eve online ? or is that a space ship simulator ......

" Eve online ? or is that a space ship simulator ...... "

" @turbomonkey138 said:

" Eve online ? or is that a space ship simulator ...... "

Eve Online is actually a boredom simulator. "

Well Sins isn't really a space sim but it's a good RTS style space game. It's got quite a few mods in the works as well.
 
If you want a proper sim then Freespace 2 would probably do the job but I would definitely avoid the X games since I find them to be quite tedious. 
 
Like others have already said, Gal civ 2 is pretty good fun when you get into it.

I played starlancer alot when I was a kid, and I really enjoyed it. It's similar to freespace.

I'd get FreeSpace 1 and 2. Sins is a good 4X RTS but I wouldn't say it's quite as good as Homeworld.

I'm going to repost my opinion on the X series. The series is not at all user friendly and is not meant for casuals, but if you're willing to put in the effort it can be very rewarding. The only downside is practically everyone comes out of it wishing their was a multiplayer equivalent. There isnt. The games can be buggy on release but they are very quick to respond to community feedback and quick to release patchs.
 
Very good community based around the series also. Lots of great mods. Hell even the latest expansion pack was basically a repackaging of a massive usermod that the team recognised and made commercial.

Independence War 2 was relly good when i played it and it still looks alright

I ended up getting Sins. I kind of like that games will take a long time because I don't mind going slowly and I don't have any pressure of finishing a game in one sitting.

Darkstar One is awesome once you get past the shitty voice acting. 
 
Well that can be said of X2, X3, hell any space sim. 
 
EXECPT for Tachyon: The Fringe, another title I recommend, featuring the voice talents of Bruce Campbell as the main character. 
 
Enjoy.