Ground troopers:
Empire- Anything besides shock trooper, I love the empire.
Rebels- Probably engineer, because the rest just don't suit me very well :/
CIS- Sniper or engineer because I don't care for the slow blaster on the SBD.
Republic- Any but the last favorite besides rocket is the soldier because something doesn't fit right with me for some reason.
Spaceships:
Empire- Any ship is fine with me.
Rebels- X-wing is probably what I'm best with.
CIS- Bomber or trifighter, but the trifighter is kinda weaksauce.
Republic- Arc.