Beau

The art itself is very close to being extinct, but there's still some info here and there. I remember hearing claims against Choi Hong - Hi, saying he couldn't have learned about Taek Kyon as a kid, since the style was pretty much dead at that time.

Either way should really work out, depending on how you train. TKD gets a very bad rep these days for a few reasons, but it can still be useful, provided you train right. (no one expects you to do a 720 spin kick except for show) Muay Thai, on the other hand, can get you in the right shape much faster, (and alot stronger) but they'll work you to the bone.