What camera and gear do you have?
I have an adventure 7 which is a backpack. It works perfectly for me when I want to carry most (or all of my gear): room for Rebel XT with lens on, plus has compartmenst for 4 more lenses. I use those for 2 lenses and battery charger/extra battery. Occassionally (okay, rarely) I carry my external flash (man, that's $400 I'll never get back!

) The front zip compartment carries extra CF cards, and the top compartmant (which also has a handy interior net pouch) carries my manual, a paperback book ("Field Guide to the Rebel XT), pen, paper and anything else I need for the day (snack, wallet, etc). I originally bought the Adventure 6, but had to return it b/c the top compartment was too small to be useful (couldn't fit my paperback user's guide). Also, I love that the backpack has a side pouch for my phone and a water bottle.
Recently I added a Tamrac Express 6, for when I didn't need the full backpack. I was looking more for something I could wear around my waist, but went with this instead. Mine is khaki colored, doesn't look like a typical camera bag. I can fit in the camera w/ lens and one extra lens, but it is a very tight squeeze. It is easier to acccess the camera a little more quickly than a backpack, though.
Both these bags are comfortable and have each been schlepped around WDW for commando tours. I must admit, however, my shoulder was relieved the day I left the camera and Express 6 in a locker for a while at MGM...
I also looked at, and really liked, the Tamrac Velocity, which was a more sling-type bag (and, I believe, also included a waist belt). Ultimately, the Express 6 better served my own taste. Here's a pic of the Velocity 7; like the Adventure and the Express, they come in several sizes:
All in all, I've looked at many products, and really like the Tamrac line! Your choice will depend on budget, taste, specific purpose/need and mostly, size/amount of equipment you are hauling!
BTW, I am borrowing a friend's Canon 30D this week. Her bag contains camera with lens and an extra zoom lens, plus peripherals. It's a case logic bag, very sturdy, completely serves its purpose and I'm sure cost less than half of either of my bags!
