I love Paul Smith wallets. I personally love the black wallet with a tiny pinup girl in the corner printed on the leather. Its a few seasons old, but they might have it on ebay. Some are awful, but a lot are fun with just a touch of color to make it look funky.
If he wants something really classic and timeless, you could always go for a Smythson wallet. They're really durable and very well made. I have a personal/business card holder as well as several leather covered books from them and it's gorgeous.