I just love Neville Longbottom, because he was not gifted with like a billion talents and he overcame his insecurities, even though he was bullied and people just laughed about him. Draco Malfoy was a really interesting character, because he was expected to live a certain life. Even though he was just mean all the time, especially in the first few books, he was struggling hard with who his parents are and what they turned him into. That very same struggle had Voldemort too, I liked that character too. Okay, that just from the books...
In the movies, Snape actor Alan Rickman did an incredible job portraying him. Rupert Grint had a really charming and funny way to play Ron, which made me love that character a LOT.