Deco, are you looking for a "functional" martial art? Like a style that is actually useful for fighting?
Personally, I have a had some experience with Tae Kwon Do, Jujitsu, Krav Maga and martial arts tricking (the flashy stuff). Also, I boxed for a couple years during college and have been doing Muay Thai for the past year or so. Based on my experiences I can tell you that...
Krav Maga
Like everyone else has mentioned, this is brutal. The whole focus is dealing the most damage in the shortest amount of time. We're talking eye gouges and knees to the groin. Most of the techniques are taught from a neutral stance, meaning that you can be sitting there walking backwards with your hands raised like you don't want any trouble.
Boxing
IMO this is core. Boxing teaches you how to throw punches correctly, how to breathe, how to read the opponent, how to stay balanced and move. Also, the more you box the more you figure out that boxing isn't about your arms. It is about how you move you feet and hips.
Tae Kwon Do
Point sparring... There isn't too much more I can say.
Muay Thai
In practice Muay Thai is about as brutal as Krav Maga, minus the "dirty" techniques like eye gouging and groin kicks. Muay Thai turns your whole body into a weapon; legs, arms, elbows, and knees. Most of the focus is on balance, power, and attacking while defending/defending while attacking. For example, if you have good balance and know how to block a kick correctly your opponent will actually get hurt instead of you. The kicks are designed for maximum power and are delivered through the shin bones instead of the feet like most of the other styles. Unlike most traditional martial arts this style is good for both fighting in a ring and for whatever situation might present itself of the street. There are two downfalls to this style. 1. The Thais are ****ty boxers and 2. It doesn't cover any ground work.
If you're looking to take multiple style and are looking for martial arts that are focused on fighting I think that taking Muay Thai, Boxing, and Jujitsu will make you a well rounded fighter. If you're looking for straight up self defense then Krav Maga would be a safe bet. If you're looking for tricking then gymnastics mixed with any of the traditional martial arts should be fine.