I've also got an Oxford bag, seems pretty decent and waterproof, not too dear either. Though after recent experiences with Oxford kit I'd steer clear of them!
Just bought a couple of Cargo tail packs for Z and I too, well made, complete with rain cover (separate shaped plastic bag basically) and expandable from 15-22 litres. Looks like it'd hold my laptop snuggly along with a reasonable amount of other stuff. Bonus to this is it's not nailed to you! Just that little bit more comfortable I reckon. It's got a carry handle and shoulder strap too. Basic Cargo tail pack - cost me £26.99 from
www.sportsbikeshop.co.uk though they seem to have dropped it from their website.
To keep your laptop cosy this sort of thing looks good
http://www.getgeared.co.uk/MOTO-DETAIL_ ... tegory=203There are loads of choices though - Google search for 'motorcycle luggage' and you'll see!
I'm never lost. I know exactly where I am. It's just not where you are.