Nightengale,
Yeah, that's what I'm most worried about. I actually did my first martial arts training in TKD with my brother -- one summer, 3 hours a day, 5 days a week, everyone gets a pounding. I was 19 then; 11 years later, as I start Kenpo, I still have to unlearn my unpracticed TKD info to learn the new Kenpo stuff because, as you implied, the two arts are incompatible in just about every way. I don't know if I want to do that again. I know I want to do American Kenpo as my core art, but there's more to consider than just that. He's my brother and first instructor, after all, and this will be the first time we've lived near each other. And, his hard-core, comprehensive take on TKD may be the best stuff in the St. Louis area. I just don't know yet (no offense, Dan -- I only know you online so far, so I can't yet compare).