Although I feel there is no perfect diaper bag (especially not a one sizes fits all). We all have so many different needs and wants. I do love my diaper bag and I have to share. It is the FLEURVILLE SLING TOTE. You can read about the details on their website http://www.fleurville.com/products/sling_tote.html but here are the things that I love about it.
-It is stylish, yet functional
-It has a plastic exterior that you can wipe off, so it looks great even after lots of abuse
-It has great pockets for organization
-It comes with hooks that you put on your stroller handles and you can hang it from the
handles. (This is my favorite feature because it hangs up high on your handles so you can access it very easily while you are pushing your stroller and you aren't trying to cram it in the tiny stroller basket).
The main drawback is price! It is a steep $150! I of course did not and will not pay that, so I bought mine from Fleurville for less because it is one of their "flawed bags." You can also sometimes find good deals on ebay.