I probably forget to bring wallets maybe 4x in my life. I have this small area on my desk that keeps all my stuff to go - keys + wallet + watch + BB. My wallet is very "minimalist" - it has all the necessary cards and ID. rest = i keep it home.
I carry 2 wallets because 1 is for personal use (credit cards + ID + couple of cash) and other is for work (ID + security pass + bus/subway pass). both are very thin. I don't really understand why men keep wallet in their butt. I don't see how is it comfortable. You're going to develop SCOLIOSIS! I also don't understand why men keep all the junks in their wallets like 1 year worth of receipts and business cards.