The colors catch my eye at first, but then I take a closer look and love looking at all the previews and layouts made with the kit. The layouts are pretty much what sells me -- if I dont think I can scrap with the kit, no matter how beautiful. than I dont buy it.
I also love Bundles! I love clusters, but dont like to take all the time to do them. Fun word art grabs me too (since I stink at that).
I like to have a variety of papers in a kit, but I struggle with scrapping with patterns, so solids and texture always draw me in.