I have 23mm Conti Gatorskins, and have hit my fair share of potholes, cracks, construction plates, etc. without a flat. I do always make sure to keep my pressure up to avoid a pinch flat, sacrificing a bit of ride quality. One time I forgot to put air in the tires after the bit was sitting for a bit, the ride was definitely softer but I did fear a flat, maybe not justified as I didn't get one.
I have been thinking bout trying to put 25mm on the bike, but even those will be a bit tight, particularly clearing the brake taking the front wheel on and off.
I am looking for a new commuting bike, more of a cyclocross/touring bike then my roadie, and plan to try wider tires, 28 or 32, but more for comfort then for fear of flats.