Coach gets the nod from me, but an even more minimalist version than the card cases mentioned elsewhere in this thread: the Mini Skinny. Mine happens to be a lovely shade of pink but don't let that scare you boys away, they have manly colours too. One pocket - that's right! ONE pocket - on the outside fits the four cards I need (1 debit, 1 credit, DL and 2 business cards or my Starbucks card). The interior pocket is zipped and hides the key ring, quarter-folded cash and big coins (loonies and toonies, which will be understood by only my fellow Canadians or those who love us). All other coins find an immediate home in charity tins at the store. As for the loyalty cards, I have a plastic sleeve wallet insert that sits in my car's console for shopping trips.

Of course, this teensy minimalist wallet finds a home in one of my many huge handbags that can hold my 12" Powerbook, a complete "face" of makeup, my Treo and headset, a large water bottle, a spring jacket... but at least my wallet is tiny. And darn cute.