Bag suggestions No. 1,000,000 : For bicycle commutes

[Sesshi]

I already have an axio urban but I'd like something a bit roomier and perhaps better protecting for a notebook computer.

Maximum size of a machine I'll be carrying is practically speaking a 13", and not a Macbook. Anything heavier I wouldn't carry in by bike. Needs space for lock (I use the Abus Granit segmented 'cable' lock), everyday odds and ends, lights, glasses, and possibly a spare pair of trousers / t-shirt etc.

Thanks

 

[techound1]

I use a NorthFace backpack with a built-in sleeve - lots of room for extras.