I wear a backpack while I ride now, I don't really mind it since I barely feel the weight on my back after a few minutes on the saddle unless the bag is overpacked and poking me in the back. I don't even mind the sweaty back since it will be absorbed by my jersey or I could just take off my shirt and feel awesome. My only problem now is that the back contact area of my backpack is covered with a very soft material that soaks up all my sweat and whenever I ride to school my backpack is wet with sweat, sometimes when I ride with my shirt off even some items inside the backpack have sweat on them. Even when I drive and have a dry backpack, I can still smell the mustiness of my backpack, it doesn't stink though so I don't even know if I'm driving people away.
Now I'm looking into a new bag (specifically a timbuk2 hemlock) and want to know if it's a typical thing to have your backpack soaking wet with sweat? Are all bicycle specific backpacks backed with wicking material? I know panniers are awesome but I need the quick, affordable, carry-it-all, transport option.