My favorites: Turn A, Zeta, Original, CCA, Victory, and X. (in no particular order)
Least favorites: last half of GSEED (as idofgrahf said, it turned super robot in the last half
), Wing wasn't bad, but I didn't like how the Gundams were nearly indestructible for a lot of the fights, and I especially didn't like the "Invinceability Factor" (Hilde should have been
sooo dead after taking that many Vayeate beam cannon shots in the back), and GSD...well, yeah, it sucked.