That's a good question. My favorite would be:
1. Groundshaker, I LOVED that battle, it wasn't too easy, and it wasn't to hard. And the thing was FREAKIN' HUGE!!!!
2. Xaldin, because he was extremely hard, and it felt good when I KILLED him! jk, I really liked it (after I stopped punching myself in the leg when I lost!)
-Sig credit goes to PhilXZ. The pic of Kairi's head was cropped by Rathalos9. Apparently no one else can crop Kairi's head...