FreeOrion
video: FreeOrion testplay (best viewed at 720p HD)
FreeOrion 0.4.1 has been released a month ago. There still is no manual ship combat mode and there is a certain sluggishness regarding GUI responsiveness but the beautiful audio and graphics and consistent writing are definitely worth a try.
You can check out a preview of current 3d ship combat tech demo in this video (7m30s in).
Xonotic
I have been playing Xonotic on the [MoN] Vehicle Gameplay server and quite enjoying it lately. Just recently, a first version of Unsealed Trial 2 (screenshots) has been released there.
Some helpful vote commands:
vcall timelimit 600 (for when the time is draining too quickly)
vcall gotomap unseal (for when you realize that Unsealed Trial is the only playable map ;) )
If you'd like to record your own videos, all you need to know is on Xonotic's Democapture wiki page.
