Private sale is financially pretty much always the best way to go. Trading it in is however much easier. Particularly if you still owe on the car.
I bought my Camaro then listed my old car for sale and sold it in about a month or so for $3k more than the dealer would give me.
Mods: BBK Intake, BBK LT's and High Flow Cats, Corsa Cat-back exhaust, Hurst short throw shifter, SLP skip-shift eliminator.
7/1/09 Placed order for IOM/IO int/ SS/RS 6M
9/26/09 Took delivery!