For the first time in a decade, MTV has become associated with music videos again. Their new site, MTVMusic.com, has every music video ever made (supposedly). That is dang cool news right there. So far they've had every single video I've searched, and all of them are available in fullscreen display if you want. Prepare to waste a whole bunch of time!
(EDIT: The site is getting pounded like a rented mule right now, so if stuff won't load, just be patient.)
Here's a couple just to get you started. A classic:
And two from one of my new favorite bands, Paramore (Jodie probably knows these guys, they're from Franklin, TN. Y'know, Jodie even LOOKS kinda like Hayley Williams...SAME PERSON?!?! Perhaps...) The second one (That's What You Get) is featured on Rock Band II.
And for Halloween: