Why not have the best of both worlds?
I carry this wallet, for everyday use. It's a money clip/wallet hybird.http://www.ebags.com/victorinox_swis...?modelid=14913
It has (and continues to) serve me well.
There is a certain elegance I think with carrying a money clip, not to mention keeping bills organized.
However, the downside to money clips are:
1) When travelling by air - it always sets off the metal detector. The TSA guards will force you to run it through the x-ray machine. For folks that don't like to part with their cash this can (and is) a problem. I find it cumbersome.
2) Money clips make sence for US Dollars, with it's uniform size. When travelling to other countries with currencies that come in different lengths and sizes, it gets a little messy.