There are many famous and non-famous wizards in the Harry Potter series. Which would you like to duel, and why?

I'd like to duel Lockhart to show him who's boss, and to also prove that he isn't flawless. Also, he really needs to stop his Obliviating game that he's got going on.

Also, happy Battle of Hogwarts Day. May we remember those who lost their lives to save today's wizarding world.