The Rocket Hog, Grizzly, and Anti-Air Wraith are my favorite ground vehicles. For air vehicle, it would have to be the Sparrowhawk (better against damage and has missiles). The Shadow would be my favorite in terms of design, only downside is having to rely on Marines to shoot for me. Though I would like to get my hands on a Heretic Warthog (aka Needler Hog).