The only things I like to carry with me when I am out are my iPhone and my wallet. I carry everything in a front pocket so I don’t have to sit on my wallet in the car. If I could shed that wallet and just go with my iPhone things would be much more streamlined for me and less junk would be in my pocket.
The only think I ever use in my wallet are my drivers license, debit card, and the grocery store discount card. Speck has a new case for Verizon and AT&T iPhone 4 users that has a slot in the back that will hold three credit cards for you. The case is called the CandyShell Card and it has a slot on the back for your cards to slide into.
The slot is rubber inside to grip the cards well and you can put in one or two cards and they will still stay put according to Speck. This is the perfect case for folks like me that want to ditch their wallet. The CandyShell Card case sells for $39.99 (USD) and is shipping right now in white, purple, and gray colors.