bellatrix would win

for sure

Bellatrix learned form Voldy himself and was known to have be able to use mental magic. She's merciless and not afraid to use unforgivable that makes her more dangerous. She's also took on 3 witches at once (one being Hermione) and had the upper hand. I say Bella has the upper hand.

Personally I believe Snape is the most powerful wizard after Dumbledore and Voldemort (not including older great wizards like Grindelwald etc). Snape has also learnt dark magic from Voldemort. It's implied that he's very skillful in curses and other stuff. Bellatrix is always taken by enthusiasm, while Snape is always concentrated, therefore I think Snape would win. It would be a very tough battle though.

Bella is more of the "scream and shout" type... But I think Snape actually is a "better" wizard when it comes to it...

zanhar1: He learned form Volemort too. Flying, for example.

But did he take down 3 witches at one; one being the smart and powerful Hermione? Did he single handly overpower Hermione? Did he take charge of all the snatchers and a group of death eaters? Had he been shown to kill a fox (persay) with just his mind?

I hope so

I believe it (character bias aside, I promise ;) )!

Hands down Snape