There's also the "full game" mode of Star Control (part of GOG's Star Control I+II pack) -- the heart of the game is action, Space Wars style, but in the various Full Game scenarios (including those you can create), you must expand and protect your territory wisely.

There is also Star Control 3, which I consider more a 4X-style spin-off of the original.

Hey, speaking of space opera adventures (e.g. Star Control II, Freelancer), where's Starflight?

And for RTS games, anyone mention FTL?

You know, even if the combat parts happen in real time and there´s a little bit of strategy involved in choosing your route along the way and choosing which fights to pick....I wouldn´t call "FTL" an RTS.

To me it´s more of a gamified "follow your own adventure" kind of book with RPG like combats.

Get Distant Worlds: Universe.

If you're looking for a focus in any area of the game all you need to do is Automate every other aspect of it. Hell sometimes when I'm on break I let the entire thing automate while I go watch a movie with the family or something. I come back and the game has done a better job than me for crying out loud!

I highly recommend Space Pirates and Zombies. It's a top down, 2D, procedurally generated action-shooter/RPG/strategy/adventure game and it's right here on GOG for $9, which is totally worth it at that price. It's a bit grindy at times, but it's got a lot of charm and it's hella fun. The learning curve is nicely paced. The devs are working on a sequel too, which is looking more and more awesome as it progresses.

Sins of a Solar Empire: Rebellion is also a lot of fun and really addictive. It might seem a bit intimidating when you look at it, but it's got some fairly easy to understand tutorials. There are one or two elements that you might have to figure out on your own, but if you take the time, it's well worth it.

Another game that seems worth looking out for is Starpoint Gemini 2. It's on Steam Early Access right now but I'd recommend you wait till it's finished. It certainly looks promising, so I think it's worth checking in on every once in awhile to see how development goes, but so far the general consensus of the people who've bought it on Early Access is that it's really fun.

There's also Ring Runner. In some ways it's like Spaz, and in my opinion in many ways it's better. But i guess the strategy is more controlling your own ship than having a fleet. (there's only a few cases where you would control more than one ship, and even then the AI takes care of most of it).

I've said about RR that it's like a breath of fresh air, that it's like Operation Inner space, only updated for newer systems. But then there's the story, the adventure. Every mission is different and it feels far more alive than Spaz. I especially like the stealth missions :)

To many games, not enough time, still, thanks for the recomendations
I prefer RTSs and as for empire building, it dosen't matter to much if the game has it or not