I got a bit carried away with the explanations here (not to mention the video evidence) so I'm gonna tackle the other two Top 5's that beansidhe_baby asked me in a subsequent post. If you want to join in, leave me a comment and I'll try to think up some good ones for you too.

Top Five OTPs
(I guess that should really be FTPs - "Five True Pairings?" Heh.)

( Bret/Jemaine, Jack/Stephen, Dom/Billy & Merry/Pippin, House/Wilson, Olivia/Elliot all elaborated on (and youtube-ed) behind the cut )