Hmmm... a lot of mainstream shounen battle manga here... I guess it's my duty to change that
1: Pandora Hearts - As if a psychedelic, twisty, amazing plot and BA, awesome characters weren't enough to gain Pandora Hearts my top spot, it also has the best art if ever seen. Period. (Well, except maybe Death Note, but the art styles are so different that it's not really easy to judge.)
2: Ouran High School - sure it might be for 'girls' and it's genre is 'romance' but that doesn't stop it from being fall-of-your-chair-laughing
FUNNY. 3: Spiral: The Bonds of Reasoning & Record of a Fallen Vampire - Both by the same amazing Mangaka; Kyou Shirodaira. Every. Single. Friggin'.
Second. Is a plot twist you didn't see coming. Two of the most awesome mysteries you'll ever find.
Death Note would probably be on here if I ever read the Manga... There, I admitted it! I never read it