Sexyback Chords by Justin Timberlake

The song doesn't use power chords but if you are playing it on guitar it sounds better 
just playing the root notes. Basically it's

Verse and Bridge:

A A#A A# AAA A#A

You can figure out the rhythm.

The chorus is

A Ab A A# A Ab A repeated 
over again

That's pretty much it for the chords.

Lame song, I know, but catchy and chicks dig it which is why we all play guitar in the 
place.