I'd go with a JKD, BJJ and Kickboxing/Muay Thai mix. Kickboxing is very good for building power, speed and devastating striking power, provided you adapt the high hand stance and angles a little to account for the lack of gloves and the possibility of groin attacks. Muay Thai will get you the devastating knees and elbows. BJJ is for up close and takedown situations, although in general you wanna stay off the ground in streetfights. And JKD combines a lot of the others with some very effective locks, punches and traps, extremely effective in a streetfight. I've trained for a while in all of the above and have had to test them on the street more than once.
If you really want to push the barrier, train in Kali for knives.. nothing is more dangerous up close than a knife and someone who knows how to use it. Of course, it might be worse if you end up stabbing somebody rather than take a beating but in a life-or-death situation the knife skills are handy.