Kyokushin!
Kyokushin is awesone!
Here is a show called, "Fight Quest." Two guys go around the world and try out different martial arts. One of them they tried was, Kyokushin Karate, in Japan. It is several episodes long but it's worth it to understand & like Kyokushin Karate. After I watched I wanted to do Kyokushin. But, sadly, there is no Kyokushin Karte schools around in my are, you are lucky. Anyway here is the link to the first episode:
http://www.youtube.com/watch?v=cVAHJp7YfGo
The other Karate styles aren't bad but Kyokushin is more practical. It also fits exactly what you want: lots of sparring and 50/50 punches & kicks.
Have you see Kyokushin competitions? You fight full-contact. The blows are above the waist. You cannot punch to the face. So, there is a lot of body blows. The K.O.'s come mainly from head kicks. It is brutal. If you can survive that then you can survive a lot of attacks.
The other styles won't have sparring & competitions like that. They will mainly do point-sparring (light contact) and katas. It won't be as practical.
Take Kyokushin!