I always thought the MLC-3 (tank-like thing with the bubble canopy and two laser canons) was the only legit one in terms of NOT looking odd should it appear in a film. A figure could be put in it and there was zero chance they would randomly fall out.

I always hated the PDT-8 (non-descript flying vehicle shown w/Threepio and FX-7). As if it wasn't bad enough that each of the two chambers could barely keep a figure in place, IIRC the end flaps snapped down (like a pick-up truck's tailgate), as if the figures needed an easier exit!

CAP-2 was cool if imagined as Bossk's little vehicle. I guess it was supposed to fly, since those legs weren't too stable. And I assume the Rebel Commander was his bounty. I wonder what was in this guy's past? No doubt the EU has explored this. ;)