None of them? It's like you picked some of the worst artists, and paired them with great ones. I don't think any of these collaborations will ever happen.
Can you imagine these?
Taylor Swift feat. Lil Wayne
Madonna ft. Justin Bieber
Ne-Yo ft. Paris Hilton
Lil Mama ft. Nicki Minaj
Colbie Caillat ft. David Guetta
Nickelback ft. Shakira
Linkin Park ft. Gwen Stefani