What is the most practical martial art to learn?

Krav Maga if you just want to learn to protect yourself. I like all martial arts and the structure of it all but Krav Maga takes all the good things and uses the best of them all, it's kind of like Jeet Kun Do. But it's really up to you what your looking for. Go out and try different styles and find out what you like.

CH (MAJ) William Beaver
Both Gi and No-Gi Brazilian Jiu Jitsu combined with MMA training. Even if you don't want to fight competitively I think it is one of the absolute best all-around self defense arts and it's a great way to lose weight and get/stay in shape.

I've practice Shotokan Karate and Tae Kwon Do for some time. I have enjoyed both and find myself combining certain aspects of each. I would research a discipline that can be adapted to you. I'm 5' 5", which means that I have to leverage speed and power. TKD offers speed and kicking power. What Karate gives me is raw power and the ability to come in bottom up.