What can you do? Well, you don't have to send a takedown notice or sue.

From Techdirt, a question -- who will be the first to sue Girl Talk? I don't think it will be LL Cool J -- and mention of a small industry of "sample trolls":

[W]ith over 300 samples used on the album, there's almost certainly going to be a few who get upset [by the Girl Talk album]. . . . [T]he woman in charge of the copyright for the band the Guess Who is planning to go after Girl Talk, noting that: "We'll chase it down. What more can you do?" Well, actually, there's plenty more that you can do -- such as recognizing that no one who hears the music on Girl Talk is going to see that as a replacement to the Guess Who's album -- and, if anything, it might entice new fans to the original.

But, eventually a legal battle is going to pop up -- and while Gillis and his label are banking on "fair use" claims to protect them, the history of court cases on this particular question have shown the courts (wrongly) seem to count nearly any require a license. This has created a small industry of "sample trolls" getting the rights to various songs (often via very questionable means) and then suing anyone who samples just a few notes from it. It seems quite likely that sooner or later someone is going to go after Gillis for this.