My wish would be to get terminal cancer.
Then, when the Make-a-Wish people show up, I'll wish for two more wishes, and then I'd wish for my cancer to be cured.
NEVERENDINGLOOPMUHAHAHAHAHAH
But honestly, I would just want to meet [a href=http://www.youtube.com/user/boburnham]Bo Burnham.[/a] He is just such an amazing guy, and it'd be a great experience to get to know him I reckon.
EDIT
I suppose it should be mentioned that I actually used by actual [a href=http://tvtropes.org/pmwiki/pmwiki.php/Main/IncrediblyLamePun]Jamaica-wish[/a] to meet up with the awesome (actual) folks at [a href=www.roosterteeth.com]RTHQ in the Greater Austin area.[/a]