I hate having to tote an extra 10 pounds on my 22 mile commute to work. But it's the best way to carry laptop. The bonus, though is that I have room for spare inner tube and extra clothing, etc. It does seem weird when I bike on the weekend without the backpack; it feels like I am forgetting something when I walk out the door!

I am not interesting in putting a rack on my CF road bike.

I have gotten used to sweaty back.

This thread is missing the "no real biker uses a Camelbak hydration pack" :-)