15mm scale Infinity!
OK... why? Because I've been looking for a decent skirmish game for ages, and I like the way Infinity plays - and I could get much more mileage from, for example, Ground Zero's 15mm StarGrunt SF range as far as troop minis go. Plus there's little need to convert for the right standard/support/heavy weapon types as they've a pretty comprehensive range, whereas the Infinity minis - at least when I first got the beta rules - were pretty limited.