I've listed some of my doubles on e-bay.

AFA 90 TRU Starscream
TFC #10 Soundwave & Laserbeak
TFC #1 Jazz
TFC #12 Minibots
Vintage G1 Hook on sealed card

I put em out there to start at prices I would bear to let them sell at. I've got watchers on all the auctions but the TFC #1 Jazz.

I'm going to wait until after the movie is released before I list any of my more common doubles in order to gauge the movie hype.

EDIT: Watch out for when this dude lists:

http://search.ebay.com/_W0QQsassZredwagon69QQhtZ-1

Instead of pricing the items based upon completed sales, he starts his auctions at a penny with no reserve. It hogs all the attention.