Portraits in Dramatic Time
This isn't really a Snape video, but it has the next best thing; Alan Rickman. This was basically a short film he did that probably took one minute to film, but its slowed down so much it's seven minutes long. I, for one, think it's the sexiest thing I've ever seen.
Some of the stills in this are just so awesome, I want to die when I see it. It's sexy overload. There's also no sound, so you focus more on Alan's sexiness.