Gandalf, are you thinking of Runesword? It was a game offered by Shrapnel which went open source (if memory serves) after all copies were sold.
Vega Strike is quite impressive (I haven't checked the Privateer mod), and certainly a game with a *lot* of potential. Hmm...
My turn to offer suggestions:
The Babylon flight-sim for another space-based game, though this one is much more focused on combat. If you have ever wanted to fly a Starfury in an inertia-based game, it will fit the bill.
www.drod.net, aka DROD, for a formerly commercial game which went freeware (interestingly enough, the original creator is on board). It offers a puzzle dungeon crawl, so the main means of solving puzzles is a good old-fashioned sword and many obstacles are monsters. For the most devious players, there is also a level editor, and quite a few wicked player-made levels have been released; meanwhile, the sequel is reaching completion, and will still be freeware.