Have you guys ever based any purchase decision on manga or anime on the cover? How has it worked out?
I mostly make my purchase decisions on books (yeah, I'm a reading freak) based on the cover. I scout the bookstore, and if a cover catches my attention, I read the backcover, and if I like the summary and the budget allows it, I get the book. Of course I take recommendations, but I've managed to discover some of my favorite books by picking up something from the newest books sections.
I tried to use the same approach on anime too. I got the 3X3 Eyes boxset just because I really liked the cover, and Fushigi Yuugi because I saw a pic of it, and I loved both of them. Then I purchased the Earthian DVD just because it looked stunning. Hot winged guys, what could go wrong? I absolutely hated this DVD, and seriously regreted it 23 bucks for wasting a bit more than an hour of my time. At least books last me a bit longer! After that, no more purchasing any anime without checking at least a few reviews.
Manga is a bit cheaper, so although I learned my lesson and now mainly buy based on at least a minor knowledge on the series, or recommendations, attractive covers still do it for me. I started getting Angel Sanctuary just because of Kaori Yuki's stunning art. And I'm for sure not disappointed.
How much does a cover influence your actual purchasing/watching decisions? What other factors do you take into account?