Last year I finally got fed up with my bulky bi-fold wallet: the same design I'd been using my entire adult life. I read this article about all the wallets on KickStarter and used it as a the basis for some extensive research into different wallets.
I narrowed it down to a few that I thought were most promising and ordered them all. After trying them out, I settled on the Crabby Gear as my wallet of choice. It's inexpensive, very thin and light, and has reasonably good access to the contents. One minor downside is that in order to fit cash in it, I had to learn how to fold bills into thirds.