Kevin, its worth exploring Discogs in detail.
Discogs is proving quite the valuable resource for me. As my vinyl revival gathered pace, I set up an account and created a ‘Collection’, then used this to catalogue my old records as I went through them all. Its proved a very helpful archiving / valuation online database, especially as to the potential value of some of the old / rare discs (jaw dropping in some instances - worth how much!). Vinyl done, and bout half way through the CD’s at the moment.
There's also the iPhone App. Link this to a collection and can call up the database when on a shopping spree to check whether an album is already in the collection. That alone is a very useful asset.
And then of course, there’s the wallet damaging ‘Wish List’ facility. Once set up and populated with albums being sought, it provides a list of registered Discogs retailers (private & commercial, with full feedback details similar to ebay) selling examples of these albums. Regular emails are sent out when new albums on the wish list become available - this really tests restraint!