In reply to goldmember:
My commuter has a hub gear (Shimano Alfine-11spd) and while it is virtually maintenance free it's not without its problems, the 8spd is meant to be better but doesn't have the gear range. On a bike costing in the £7-800 range you are unlikely to find the 11spd as it costs around £350.
Pluses: it is virtually maintenance free - you do have to change the oil at regular intervals but for me this works out as being just once a year. No chance of bashing the derailleur and losing your gears. You can change gear whilst at a standstill, i.e. traffic lights. Less chain wear. They are very quiet.
Minuses: You have to keep the change cable correctly tensioned otherwise the gears can skip, it's not a hard operation: just align a couple of dots when in a particular gear. Removing the wheel needs a spanner as you can't use a QR skewer because there's no sprung cage as with a derailleur to take up any slack. You have to ease off the power when changing gear.
Belt drives: not used one but you need a special frame to use one as the chainstay on the drive side has to be able to split as you can't split the belt drive itself like you do with a chain. They do perish over time. The biggest benefit is not having to oil them.
I'd also look at a dynamo hub to power your lights - you don't have to worry about batteries being charged or forgetting your lights. They do take a bit of power but it's not really noticeable on a commuter.