Thanks so much for the suggestions, everyone! I made up my mind and actually got 3 things for different needs:
The Lug Hatchback mini backpack, in black, for long walks when I'm wearing the Chickadee:
http://www.lugtravel.com/produ.....kpack.html
A duplicate of my Nine West Flying High Large Hobo, in black, for the winter (it's my main bag right now in the summer)--I LOVE this bag, and the fact that it's not real leather is a bonus:
http://www.ninewest.ca/store/p.....uctid=3556
A secondhand (read: cheap!) Kecci Shanghai Mommy Bag in red silk brocade that converts into a backpack, just for fun and to try out a "real" diaper bag:
http://images.craigslist.org/3.....4914e3.jpg
http://images.craigslist.org/3.....a01c1c.jpg
Yes, two of them are black, but I love black :P, my winter coat is red, and almost all my baby carriers (wraps and mei tais) are colored and/or patterned, so it made sense to go with black.
I'm going to seek out that munchkin wallet--maybe more than one of them, to keep in each bag and in the car. It looks like Wal Mart should have them, and we have a gift card for there.