For a city commuter bike, don't bother with disk brakes - go for simple rim brakes. You'll want the reliability over all else. You don't need disks for most types of road cycling, as the limiting factor for grip is likely to be your tyre anyway.

As regards shifters, go with whatever is comfortable for you. I like the combination of brakes and gear levers in the same unit, as you don't need to take your hands off the brakes to change gear. This is very useful in traffic.

I would also recommend touring tyres - relatively narrow, so you don't lose too much power through rolling resistance, but wide enough that you have some puncture resistance. You could also look into self sealing tyres.

For a city commuter bike, don't bother with disk brakes - go for simple rim brakes. You'll want the reliability over all else. You don't need disks for most types of road cycling, as the limiting factor for grip is likely to be your tyre anyway.

As regards shifters, go with whatever is comfortable for you. I like the combination of brakes and gear levers in the same unit, as you don't need to take your hands off the brakes to change gear. This is very useful in traffic.

I would also recommend touring tyres - offroad tyres lose too much power through rolling resistance, but you want tyres wide enough that you have some comfort and puncture resistance. You could also look into self sealing tyres.