This national geographic bag seems to meet all my needs for a new camera bag, holding a DSLR, two lenses and a laptop, with space to spare. It can also be converted to a regular backpack. There are discounts across the NG range on the manfrotto website.
The leather and canvas textiles mean it looks a bit nicer than most nylon bags.
I searched around and the cheapest I could find this for was £129.99, not including ebay.
Free next day delivery is a bonus! I think it's on anything over £75.