I get my stuff mainly from Resellrightsexpress.com which is run by Derrick van Dyke. What I like about it is the fact that the products are very well structured (Private Label Rights, Master Resell Rights, Resell Rights, Giveaway rights, etc.) and also it offers a search function that actually works. Makes life so much easier when searching for good content on a certain topic.

Oh, and I almost forgot: there is always a live preview of the sales page of the product available - given of course that the product comes with a sales page. That makes is so much easier to get a quick first impression of the quality of the product.