Some of the best vids are Jeff Dunham's, all his characters are great lol.
Another one that I really enjoy watching, and find it extremely funny:
http://www.youtube.com/watch?v=iT4azzSRcxw
And if you like to follow the news and know a bit about the situation here in Lebanon you'll find this pretty funny as well:
http://www.youtube.com/watch?v=F3PTIUR9naI