Many people will tell you many things because different personalities gravitiate towards different aspects of the martial arts. But I'll tell you my version of the truth: the art doesn't matter. They're all interesting and good in their own way. What matters is the instructor. If you find an instructor you really like because he/she is knowledgable, warm, strong, and teaches in a way you jive with... take that class. It doesn't matter what it is. It's harder to find an excellent instructor than it is to find an excellent martial art.
That being said, you'll get more philosophy and meditation with the traditional arts, and less with the Americanized arts, the "fusion" arts, and the sport/practical arts (e.g., MMA, Krav Maga).
That's my 0.02c. Maybe you'll get more specifics from proponents of particular arts.
I'm so happy that you're considering taking martial arts! I think it will be a wonderful experience and would love to hear what you decide and how it goes. =)
FKJP