[fckgw]

Agreed, I've sold on each of those platforms.

Godaddy gets the most traffic but not a lot of "prestige" domains. Good for cheap domains or ones you think could get bid up a lot.

Flippa I like, lots of sales to other domainers. Full site sales are good here as well and their broker service offers good protection. Better for mid-tier domains IMO.

Sedo is the site where most high value domains that aren't a private sale get listed. If you have a solid, valuable domain that could fetch $xx,xxx then try here.