When I had my son (years ago!), DH bought me a mini mono diaper bag (the old style). It was THE MOST UNCOMFORTABLE bag EVER MADE!!! I hear the ones they sell now (the newest style) is pretty comfy and user friendly. AND it can be used as a carry on luggage when you are done with it!
I don't have any kids now, but *IF* or *WHEN* I do lol, I'll be getting those mini lin diaper bags (if girl: pink; if boy: blue) cuz those are AWESOME!!! there are soooo many pockets that you can play around with!
I have the old style one and i still use it if we are going on a day trip , wipes drinks etc and my baby is four ! I was trying to justify buying the new one but i have to say i have loved my diaper bag !
I use my mini monogram deauville. It was a special order and is perfect becuase it has a wipeable interior and elastics to hold bottles and pockets on both sides for diapers and wipes. I have the long strap too when my hands are full. The monogram deauville would be a great choice for a diaper bag!