One Piece
Dragon Ball (that includes the later half, named "Z" in America)
Death Note
Yu-Gi-Oh (don't call me a nerd. It's nothing like the shitty anime)
I reccomend all of these, but you HAVE to read Death Note. It really is the best manga I've ever read, and is much better than most novels I've read. I'm probably going to start collecting another series soon. I've been holding off because dragon ball is 42 volumes, Yu-Gi-Oh, when finished, is 38 volumes, and One Piece already has 12 out, with volume 41 having just been released in Japan. (See how you have to plan ahead with these things?) Luckily, Death Note has 7 out now and will only go to a volume twelve. If I am going to collect another, it was going to be Rouroni Kenshin. Is that one good?