My impression include (but are not limited to) Beavis and Butthead, Homestar Runner, Strong Bad, Strong Mad, The Cheat, Homsar, a few of the little britain characters (specifically Majorie Dawes, Lou and Andy and Dennis Waterman), Goku, Vegeta (yes, I CAN do the over 9000 bit), Piccolo (to an extent), John Culshaw's impression of "Gladiator" Russell Crowe, a purposefully bad Arnie, the porn monster from Avenue Q and Stewie from Family Guy.