which Sci-fi rulesset?

[rjandron]

I see someone else has recommended Fast and Dirty. I'd second that suggestion.

Stargrunt also plays very well but the rules are very finicky--don't go changing something unless you're prepared to really change game balance. We modded the rules for Power Armour by simply allowing them to shrug off their first suppression and that just about completely unbalanced the game and made them real terrors on the battlefield. Vehicles are underpowered IMO in SG2, which given the scale of the game is appropriate. You may want to try Dirtside II as an alternative. Still, SG2 is a lot of fun to play.

Though not strictly SF, you can also try Ambush Alley's Force on Force. We played a modern game of this and it went right down to the wire and everybody had a blast. It's really geared more at skirmish level (with maximum a platoon to a side).