Rock and roll eh?
I've just got a new job in the city (swings plaits, belts out a chorus of 'there must be more than this provincial life') which I'll get to using a train and the tube, but I've managed so far with just my handbag since I go everywhere by car.
So I'm tapping in to your collective wisdom. Please help 
I'm going to need to be able to get a laptop in it, I think probably a rucksack style for ease of movement but not one that looks like I could otherwise take it hiking.
Any recommendations for a suitable bag, and in fact anything else I should think of please?