Lis of what you should see:
Great Teacher Onizuka
Gundam SEED Destiny
Appelseed (Movie)
Gundam Wing + The movie: Endless Walz
FLCL
(Quack Experimental Series) Excel Saga
Melody of Oblivion
Read or Die
Tenjou Tenge
AND MORE!
Why? They fit Shonen and Action well. Now, have a nice Spring Break
Make sure you watch all (^_^)