Wanted to mention - http://expiredprdomains.com - the beauty with these guys is that they show you detailed backlink information including if the backlinks have PR. Great for reselling or building out a Quality site without having to start from Scratch!
DDrop.net is the best for many reasons - Finds high PR REAL domains that are ready to buy for $5 - Over 150,000 domains in database - Fake and real pagerank checker - Age information on all domains - Backlinks information on all domains - Amount of Tweets and FB Shares of the domain - Daily updated database (I completely truncate the table then rebuild with new data) Social is so important these days and ddrop.net has all the data on it
You can also write/buy a script to figure out when the domain expires and grab it manually. Sometimes that works faster than automated domain grabbers. Otherwise godaddy auction is best, look under expired category. One tip, make sure you turn off the adult filtering on your account otherwise you won't see all domains. You be surprised to see how many domains are marked as adult when they are not.
I would prefer expireddomains.net or justdropped.net coz they give other details like dmoz n pr ot check other from here too http://hqtips.com/web/domain/5-best-places-to-find-expired-domains/