Welcome to RPF Emma. The search for the ideal bag is a bit like the search for ultimate enlightenment - it's a lifelong quest with many ups and downs!! The Crumpler bags are pretty good. I have one small one and I did have a large messenger style one that was pretty good - that is now in the possession of another forum member (Blanka). I have quite a few different bags but the most are by Billingham - cool in a retro way I guess. These are probably my favourites and I keep coming back to them.
Anyway, good luck with the search and once again, welcome to RPF. I'm sure you will enjoy it here. You may not find your perfect bag, but you have found the perfect photography forum!
I have a messenger style bag that doesnt look like a camera bag. Inside i have put one of my older camera bags that has nice compartments. Does the job.