um... galciv II maybe?

There was Conquest - Frontier Wars, could be argued to be "larger", and it has some connecting points with Sins. It's a three-race space RTS with solar systems connected by wormholes. It has some nice stuff, I enjoyed it but... It doesn't seem to work on newer computers It runs at ~14 FPS, the mouse is laggy and it crashes a lot.

I would recommend LineageII.  It is a multi-player fantasy game, but don't let the mental comparison to WoW put you off.  It was developed in Korea which, IMHO, allowed them to avoid a lot of the 'instant gratification' fixes that western audiences seem to demand.

You create one or more characters and choose a server, I play on Sayha.  Unlike games developed in the US, LineageII does not protect a player from their own mistakes.  Other players can scam you, kill you, grief you or befuddle you.  As a result, I believe that the players' true natures show up ingame since most of the social restraints we see in 'real life' are removed.  As a result, the people who are really good are nice people in the game while those who are not nice can be quite evil.  This results in fascinating societies and politics swirling around the game system of controlling castles, fortresses and the complex economy.

I recommend it very highly, though it is a tougher game than many might prefer.

Ahh well try any off the Total War series games too they are fun. Also the new Total War game is coming out Empire Total War in the beginning of March. Its TBS in empire management but in fights its like a RTS... and finally the naval combat is real time WOOT! I think there is a gold pack that gives you the orginal Totals Wars games too. Or try Medieval 2 Total War or wait for the new one. They are fun too.

Ahh didnt really read the title "a game like sins".... damn am retarded... still I don't think theres anything else out there at the moment like sins or gal civ 2... so ya you will have to wait for GC3.

OK please... how the hell is Lineage 2 "larger in scale" than sins? You mean it costs more or..?
I mean, I understand the Total War reccommendation, but Lineage!?
And no it's not a "tough game", it's a grind game.

Ah Regicide, a fellow Conquest FW player, eh? Loved that game back in the day, but like you said, pretty outdated now. Do people still play that online?

Hmmm, you know what would be sweet? A space-based MMORPG. Instead of a character, you could have a ship.  Group with other players to form fleets,  fly through space, terrorize  other ships.  Or  stay lone, become a space pirate. Level up and acquire upgrades for your ship.

Could be cool... I see the potential.

My suggestion is to check out "Infinity: The Quest For Earth."  Although it is still in the development stages...it promises to be way more than anything out right now.  Pretty much dynamic and in scale it far out-reaches all games right now.  This is if it works as advertised.  Check out the site and do some research on it.  I mean it looks completely amazing to me and I cannot wait for it to be completed.

http://www.infinity-universe.com/Infinity/

It is  slated to be a MMO...but offers the space theme from as far out as controlling multiple ships in a fleet all the way down to landing a single ship on a planet.  And the universe is pretty much wide open and "Infinite."

Infinity is supposed to have a single-player variant as well, something like Elite. If they do complete it, and if the sum of its parts is at least as good as the demos of those parts, its going to be one hell of a game. Even as a MMO, it may dethrone EvE as the king of sci-fi MMO's...

...a few?! You mean you didn't stop at one? You just kept going!?  

Anyway, IMHO Eve is one of the rare MMOs today that I may even consider paying a monthly fee for. Mind you, I didn't say I will pay a monthly fee for it, I just said I'd consider it.

I still think the sandbox of X3: Terran Conflict appeals to me more than the Eve feeling of "I hope noone torpedoes my warship while I sleep"...

Larger scale than Sins? Even on small maps, the games seem to take all day to finish . . .

I can't speak for RandallFlagg, but I'd want soemthing like Eve online, but with real PvE. I'm considering trying EVE, but from what I've heard it's pretty weak on PvE, and it's practically an anarchy in there. I'm waiting for something like EVE but with a much stronger emphasis on quests and PvE.

I was looking at this, very tempting, im a fan of star trek too. Might take a look.

Yeah got SC and the addon, great game, many mods available too. There is also a second one coming out.