Oh hell, I'm happy with anything on any end of the spectrum, except the chain guns, which are terribly inefficient. Though I'm very partial to Black Widows for their sawn off shotgun like stats. Low range, high damage, high power requirement, but if you have high damage, you won't be needing many shots to take down most fighters.
I don't have a Xeno character mind you, though I've been thinking of making one.
I'd have to say the Black Widows are probably my favorite non code. They consume so much power, but the effect is... SPEC...TAC...ULAR! I do agree with the others regarding the chaingun line, they have been so nerfed that all you can say about them is "Pretty". I've got the turret, but of course, I barely use it as I prefer to keep my targets in front of me.