Death Note is good. If you have a LOT of time you can always watch Bleach and Naruto. I find Bleach captures the essence of DBZ the best in the sense that it has great power ups and super fights, but Naruto has a more interesting story - the fights are decent too. Full Metal Alchemist (Brotherhood) is a great one too.
Claymore was one I liked. Nice and short and had decent fights.