If you buy a domain from a 3rd party, the backlinks are valuable. I always wait a few months before redirecting, so just set up a quick minisite until two page rank updates have passed and then go ahead and 301 redirect. However, it seems that you'll get the link juice from the back links, the anchor text is ignored by Google. Buying a domain at Godaddy TDName expired auctions, seem to not count as a dropped domain if you immediately set up a mini-site.
Once you get to this point you know there have been DMAS listed. They have a number of domains linking to them and according to the way back machine which is WBY, you can see their site age. So, if you want to go with an older site you can see right here whether or not this is a site that you might be interested in, but before pulling the trigger you do want to check two things.
"Expired Domains" will help you grab and search through all those domains that are expiring in a organized matter. You will be amazed how many good domains are expiring every day. With Expired Domains you should be able to find a domain you are looking for. It may take some time, and you should not expect to grab something like credit.com. Sometimes you will also need to use a backorder service to assure (as much as possible) that someone who aimed at the same domain as you doesn't grab it before you does.
The way this list is implemented means I can't update prices, nor removed sold domains automatically and sedo doesn't provide me with the tools I need to implement it properly. Unfortunately some users keep contacting me to update their domain prices or remove their domains and I can't keep doing that manually. So I've decided to disable the list for now.