I'm in the market for a new wallet myself.
One learning / problem:
I bought a very nice duofold Italian leather wallet in Florence (Firenze)... Basile was maker, made in Milano.
American currency is 2-5/8" tall X 6-1/16" long. Foreign currency goes from the tiny to the huge, relatively. So foreign wallets are made to hold foreign (European) paper currencies. That means they are often 3-1/2" or 3-3/4" tall by about 4-7/8" or wider when closed. It is this 3-1/2"+ height (tall enough for foreign bills) that caused me to abandon my Basile wallet. It was fine in jeans, but most of my khaki pants have slash or hidden type rear pockets. A 3-1/2" wallet is about 1/4" too tall for these pants pockets... I had to very frustratingly wrestle the wallet out of my back pocket... tilt one way, wrestle, get the edge out, tilt other way, wrestle, you get the idea. A significant annoyance, not to mention stupid looking to be wrestling around with your butt.
So if you wear pants that may have such rear pockets, make sure you find a wallet that is 3-1/4" in height.
Here is an example of a duofold wallet that is 3-1/2" tall (ack!):
http://www.davidmorgan.com/CATALOGS/DM/+H195?6887064397778537650870784352
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I find that I often want to carry a very reduced sized wallet on weekends sometimes... usually when my NAA Guardian .32 is in front pocket and I'm going out to dinner. I have a small combo money clip/two slot wallet for this task ... money, driver's license, CCW, credit card.
Problem is, on several occasions, I've forgotten to transfer the contents back to my main wallet. Not too smart.
I have decided I want to try a wallet that has a removable "satellite" wallet that serves the money clip/2 slot wallet purpose, but that can be inserted back into the main wallet and used normally that way. I.e., no transference of stuff from one to the other, just slip the satellite back into main wallet.
If anyone has found a nice version of such a wallet, please drop me a line. Here is the nicest I've found so far, but it has the "over 3-1/2" height" problem again, by a big margin... 3-3/4" height:
http://www.levenger.com/jump.asp?category=Cases+&+Bags&subcategory=Wallets+&+Money+Clips
I may have to go tri-fold, but that makes the wallet thicker-still to sit on (one butt cheek up in the air by 1" isn't good for the back).
And I haven't found a tri-fold with a satellite.