I use my own universe but I it is influenced by Traveller, BSG, Fire Fly, Warhammer 40K and Priveteers. In my new space project that has been put on hold I take influence from almost all of the above settings with a huge influence from SM2, Fire Fly, BSG, Traveller [4th and 2300] and Dune.
In fact in my last space canpaign it used a lot of Traveller books for adventure ideas, advetures, ship's, universe map, some W40K stuff, but used the races from SM:P [except for the ALF race].