I have the Nine West Baby Shopper Diaper Bag and it is awesome!!
It is small and stylish and yet holds all the basics. Will be all you need when DD outgrows Bjorn. I love how it holds bottles and sippy cups on the sides but you can take it out without baby and not feel foolish. The only down side is that is does not work great with a Bjorn or probably a sling. I love my Bjorn but take my backpack when I use that.

Here is a pic from EBAY...

http://cgi.ebay.com/ws/eBayISAPI.dll...category=15558

Happy Shopping!