During the run of the books, Snape remained a figure of contention for many: is he a good guy or a bad guy? (Spoiler alert for you non-readers still waiting for the last movie to answer this for you) How was this a question? I thought it was pretty clear ever since the first book when we learn Snape was whispering some spell during a Quidditch match not to curse Harry, but protect him. After that, it was obvious: he was a good guy. A good guy who was a jerk, to be sure, but there are plenty of those in the world.
Snape had a natural ability with potions and created several new magical brews. Outside of Hogwarts, he also mixed juices with chemicals and invented the popular Muggle drink Snapple (which he pronounced "Snape-ell", though the marketing department messed that up).
Snape's mother's maiden name was Eileen Prince, and he is the second-cousin of rockstar (and secret wizard) Prince. It's widely believed the Prince song "If Eye Was The Man in Ur Life" was written about Snape's unrequited love for Lily Potter (nee Evans). Its chorus: "If Eye was the man in your life/ Eye'd make U happy/ Eye'd treat U right/ Eye'd buy U flowers every single day/Eye'd Give U power/ Eye'd do whatever U say."