I'd recommend the Thule pack'n'pedal commuter series, particularly the larger one. It's quite versatile.
The rack attachment system can be hidden/ which makes it confortable as a messenger bag or backpack: you don't get spiky things stabbing you hips or back. And it has four strap attachments which means it can be configured as a whatever you like.
I had it for 4 years and is still going strong.
I'd recommend the Thule pack'n'pedal commuter series, particularly the larger one. It's quite versatile.
The rack attachment system can be hidden/ which makes it confortable as a messenger bag or backpack: you don't get spiky things stabbing you hips or back. And it has four strap attachments which means it can be configured as a whatever you like.
I had it for 4 years and is still going strong.