[pwnageNick]

Well actually that's not always the case.. From a legal standpoint your correct but assuming your posting the video on youtube you have to be careful. The video can and will be blocked regardless of credit given in the record label wants it to be. It's a rare thing but it happens. It's not worth it and there's good stuff out there.

I disagree. It is incredibly rare that that happens. If you give credits in the description the odds of the copyright holder having the video removed are slim. If you have a song in mind that you think would work well and that you have a good vision to work with in the video then use it. If somehow youtube takes it down you could always try uploading it on another site then.