The song only popped into my head because:
a) my wife (ok, and me) watches Glee fairly religiously and this is the more family-friendly Glee version of the song, and
b) i had the part where the beat kicks in near the start in my head for a while and knew it'd be a good place to kickstart a vid.
I used a bunch of lenses just to experiment and such, the widest would be the 10.5mm 2.8f fisheye (in the corner as they ran around the fireplace). Also used 70-200 and 50mm 1.4d.
I used premiere pro cs4 to put it together, totally self-taught in that and a LONG way to go; it was very confusing at first but I started to piece some things together after some head scratching. The biggest hurdle is that I had to convert the d90 footage beforehand using some random downloaded application before PPro would even import it. After that, things got a bit easier.