I'd suggest ignoring what those three people have posted so far - krav maga, MMA and muay thai are NOT the answer for everything, as hard as that may seem to believe. There are also multiple sub styles of both kung fu and karate, so look at some nearby schools, try out a free class or two to see how you like it, and then decide which one you're more interested in or which one you enjoyed more.
any one you want man, but with the respect of the karte, any type of kunf fu is more complete and advanced than karate. and let tell you this man, there is nothing better than a contemporaneous martial art, and one of them is the one called Wu-shu. contemporanous means that the movements and technics are not the same since thounds years ago, they keep changing for perfecionist, this is what kungfu is about, is about updating and fix the system. so think about. you can be a good martial artist with the best technics dont you think?