I always take Tali for her electronic/decryption skills. With those skills maxed out, no safe is, uh, safe. She's pretty damn good with a shotgun too. To accompany her, I usually go with Ashley's sniper coupled with high impact explosive rounds (ownage total) or Liara for indoor combat. Watching the enemy charge and then go floating off, arms and legs wobbling to and fro while I pick them apart with my pistol is pretty amusing.
Plus, with either variant I've got something to look at besides Shephard's ass while I'm riding in elevators.
Kaidan is such a jerk. I don't even know if I'm even spelling his name correctly. He's been on my crew since the start, but all he does is tinker around by the ship's lone bedroom. It's kinda creepy. When I go over to see what he's up too, he seems all worn out and he's sweating like a bastard. No dude, you can't be on my away team.
Wrex and I have worn down to first name greetings. "Shephard." "Wrex." He's just such a buzzkill, what with all that talk about the Genophage and murder and his father. Ugh.
Garrus? I don't have time for this, dude. You can thank me by running a little security on Kaidan. Creepy bastard's been hanging out by the bedroom. All sweaty and shit. Check it out. And by the way, the eye patch is out. You look like an asshole with that thing on. Fo realz.