I actually own the Stargate books, got them at a convension long with an interesting anecdote about a ferangi quartermaster in a Trek RPG he played. I never got to play it, but it is an interesting system, more detailed and thought out then d20 modern. One of trhe books also has rules for being a system lord, recuiting a jaffa army, building a space fleet, ect. There's also ship combat rules but they kinda suck. Also lots of background material up to the 3rd season, I think, or 5th, and pregens for all the major chars, even Thor, and some generic ones if I remember. It's very well suited to the DnD mechanics the show uses... those poor lvl1 marines... That said, GURPS, its awesome. Except everyone I know is refuses to play it because they're too rooted in d20, and I was admittedly a little hungover when I tried to run it.