It would be downright impossible for me to choose a single style, since I've either trained or am currently training in a few
As a kid I trained in aikido for about half a year, as a teenager I trained in judo/ju-jitsu(our sensei was a blackbelt in aikido, judo and ju-jitsu and he basically taught us a hybrid form) for two years and I've trained in capoeira for 4 months or so, when you don't count the sessions I've missed. That being said, I've taught myself a variety of TKD kickboxing techniques through Youtube's Kwonkicker(a dude who's tutorials I highly recommend). I have been very interested in combat sports for a long time now and I consider myself to be knowledgeable in the subject.
If I really had to, I guess I would pick Jeet Kune Do, since I'm basically using its philosophy - "Use only that which
works, and
take it from any place you can find it". It is focused on
realistic self-defense, and is about as efficient as it gets. But since it is "the style of no style", I guess it won't fit gotkicks2's criteria ... in that case, combat-oriented(not olympic-style) Tae Kwon Do - since it is a complete stand-up martial art which includes punches, kicks, elbows, knees, throws and joint locks if taught properly.