Lowepro AW computrekker. I passed on my mini trekker to my son with his 400D and my 70-200 F4
I've also a Tamrac Expedition 5 which I bought new from here (and never used). I thought it might be lighter than the lowepro but it's the weight of the kit. I've got used to where everthing is in the Lowepro
Both take Canon 5d with 24-105 fitted, 70-200 f2.8, 100-400, 10-22, 50mm f1.4 (under the blower) 2x convertor, 580 flash gun.
The computrekker adds a bit of weight fo rthe extra laptop pocket at the back, but it's handy when I want to take the laptop, or even for keeping papers etc flat in.