Some of my FAVORITE stamp sets are the ones I can use for many different purposes. I always try to purchase sets that I can use on cards, layouts, as backgrounds or as the focal point. To me, that's the best use of my money. I always buy the background sets, and two of my favorites are below:
|D1508: Diverse Backgrounds|
|D1477: Universal Backgounds|
And another favorite type of stamp is flourishes--you can use them on your base page to add some interest to another element, use them to frame a title, and so much more!
|C1466: Instant Memories|