Take something that is grappling and throw based, because you already have skills in kicking and striking I'd say.
I'd recommend Jeet Kune Do, based on its trapping skills (trapping of opponents hands, very useful), and it has a bit of grappling too.
I am not so keen on Krav Maga because of what I have seen its techniques in real world are less than optimal, but that was years ago, it might have evolved, certainly it is a good idea to have real world oriented situational training ie getting choked, headlock, knife at throat etc.. .... also I don't know what sort of trainers are around in the USA for varying styles. KM does however aim to keep it real.
Basically you want to build up reflexes that will save you in a situation where you are attacked unexpectedly and you are drunk, tired etc.. and possibly weak, you want a response that is automatic, takes the opponent out with minimal effort. Imagine learning a system based on strength etc.., then getting mugged after a hard session at the gym, when you can hardly walk.
I'd also recommend Bas Rutten's survival or street defense dvd to look at, that is the sort of thing to look for regarding situational defense. I am not sure where you would learn that in the US, or what other styles might teach that sort of thing.
Note also that Pride and UFC are not completely realistic because too many real weapons are removed - headbutts, kicking people on the ground, biting etc.. so don't get carried away with anything you see on there.
And stay away from things that are based on groundfighting. It is good to have that skill, but going to the ground should NOT be your strongest skillset or preference in the real world. On the ground, your opponents' skillless mate can stomp on your head and end it for you in an instant. Also, the ground is dirty and you can pick up germs. Your ground skills should be based around getting OFF the ground ASAP.
Don't write off Kung Fu either, although there are many traditional styles that are a bit restricted, there are as many variations as there are instructors, some are more oriented to real world.
I think your best bet is JKD though. You'd come out of that with great kicking, striking, trapping, a bit of situational stuff. The trapping reflexes especially if someone throws a sucker punch out of the blue, very nice.