I have dabbled in both. My brain is small and I don't want to clutter it up too much so should I use that valuable space to learn more about Motion or Livetype. It seems like Motion kills livetype so that would be the choice to make. Or is there value in using both???
Livetype is just title design, Motion is font design plus a universe of titling, visual effects, compositing, 3D. And now that LiveType has been discarded in FCS 09 and its functions folded into Motion, I'd say the choice is very clear.