Great idea for this thread Sarah.
I have bought a back-pack style nappy bag. It is just plain black and looks really nice. I wanted to get something plain so that Neil wouldn't feel like a big dork when he has to carry it around (he is sensitive about that sorta thing).
I have already packed some old cloth nappies for spew-cloths, 5 disposable nappies (but I think I will put more in after reading this post!), a dummy (it has a special little dummy-holder section that hangs off the side as well as a mobile phone holder), it came with a fold-out change pad and, like yours, Sarah, it has a sealed section for smelly-bits, nappy sacs (which smell so divine!!), one of those huggies travel wipe thingys, I bought a small zip-up case for creams etc. once I get them, bibs and many other things. I still haven't put in a change of clothes as I am not sure what size the bubs will be in to begin with and I am sure there is stacks more for me to add. I will probably use it as my handbag aswell (one less bag to have to remember).
My only vice with the back-pack style is that it may not fit over the handle-bar of the pram. I have noticed that most prams these days have a solid all-in-one bar that you can't really hang things off (like shopping bags etc). Where an over-the-shoulder nappy bag has a large strap that would fit over, the back pack doesn't. I think you can buy hooks or special attachments to be able to accomodate for hanging things??? Will have to check it out.