Starship combat games come in several categories, and the best for the situation will depend on the situation...
For fighters (or, at least, the fighter "feel") I'm likely to default to Silent Death, as cinematic as it is. If I need complexity, I'll pull out Renegade Legion:Intereptor...
For RP combats (typical traveller PC ship scale) I use a mixture of "the Referee says so" and Mayday, mostly to aid visualization...
For fleets, I've found either Full Thrust, BattleFleet Gothic, or Slag to work fairly well.