28mm is the narrowest I would consider or suggest using for a commuter bike. IMHO, Panaracer Pasela tires are the best tires I have used in terms of ride quality and rolling resistance. I have only used the non-'tour-guard' version, which apparently are less puncture resistant than the flat resistant 'tour-guard' tires. The non TG version are usually around $20 and are available in pretty much every size commonly used on bikes today.

Other good tires I have used are the Continental 'RIDE' series - not quite as nice a ride as Panaracer Pasela (As far as I can tell - but it may be in my imagination as they are both awesome tires) but have excellent flat protection and a bit more aggressive tread.

Edit: The nice thing about tires is that they are a wear item - meaning you will be replacing them eventually and can try out different tires, and different combinations of styles/treads/sizes/pressures. Tires are the part that makes the most difference to the way the bike rides, and also the easiest to change.