http://www.chameleoninserts.com (I think that's the right link) is the one I saw recommended here, and I bought three - one in each size. There isn't a lot of difference between the sizes. I am using the smallest, because most of my purses are smaller in scale since I'm petite. It works well with nearly every purse I own - even my largest Furla bag. Except for clutches. But if all your bags are oversized, I might go for the largest size.
I am loving this product - it really simplifies things and makes it easy to switch bags. You don't need a wallet - it has a velcro compartment for you cash. I am guessing after awhile the velcro will lose it's stickiness, so at that point I may get a wallet anyway (maybe xmas present - I've been hinting!). There would still be room for one.
I am giving the other two as xmas presents, the larger one for my sister and the medium one to my niece. My most fashionable girlfriend fell in love with mine, and just ordered one for herself too. She got the largest, sturdiest one because she's nearly 6 feet tall and all her bags are ginormous.
