What is the narrowest tire you would use for commuting?
For my commuting needs, I use Continental Gatorskins 700x28c.  I also use Mr Tuffy liners to help protect against punctures.  Using this combination, I haven't had a flat in 2 years.  Before going to this combination, I would get about 1 flat a month.  I travel about 14 km a day, 5 days a week, April to the end of November.

I recommend that you leave enough time in your commute to change a flat if need be.  For me, this is only about 10 minutes. Your time may vary.  My job is such that it's not a big deal if I'm a few minutes late.  If your job requires you to be right on time, you may have to sacrifice being early on the off chance you do get a flat.  

Also, ensure that your tires do have enough air in them. If you use skinny tires, a lot of flats come from snakebite flats, caused by not enough air pressure.