I've had a lot of experience. I used to like to scrap a little consensually though. I'd end up with a fat lip and a lot of laughs. Any striking art will be good. The better ones are boxing, muay Thai, and wing chun. As far as grappling, you're going to be suggested bjj. That's a mistake. Bjj is really good at fighting one guy on the ground. You mentioned that you want it for self defense. If you're fighting someone on the ground what are the chances chuds friend is jumping in? What you really want is something that will give you good defense against takedowns. Wrestling and judo are good choices. If I had to focus on one, I'd go muay Thai. If I wanted to go for fun, judo or boxing. Finding a few friends that want to throw each other around in a park, is a blast. Likewise, beating each other up in a gym is tons of fun too. If you find a really good school, you'll realize how much a street fight is about luck, but you'll be in better shape, and at some point you'll start to feel like a shark. It's a cool feeling. Good luck