In
my most recent Spaceships-heavy campaign (TL 11 ish, natural jump points requiring no special ship's equipment but several AU from the star and only going to a single other system):
- Modern warships use antimatter plasma torch + super fusion power plant
- Older warships, and pirates trying to look like merchants, use antimatter plasma rocket + nuclear thermal rocket (one for long haul, the other for tactical manoeuvres, and if you assume the antimatter is stored separately from the hydrogen they can run off the same fuel tanks) + antimatter power plant if they need one
- Merchants use antimatter plasma rocket only (no power plant needed)
- Air-breathing civilian shuttles use antimatter thermal ram-rockets (no power plant needed)
- Weather control satellites use solar panels (no drive needed)