I like to fly and drive 'em all, and sometimes have made it a point to do every airplane and ground vehicle until I have at least 1 kill in each for the tour. Helps me understand their strengths and weaknesses, although you'd never know it by my scores.
Although, over time I do tend to favor the La-7, F4U-D, P-47D, YakU and T, and Zeke -- nice blend of b&z and turn and burn.