For all the reasons mentioned I like a frame mounted pump. I have a fleet of 3 Zefal Hp pumps on various road bikes and a Zefal mini on the mountain bike. I have thought of getting a CO2 inflator but have decided that spending the money on tougher, more puncture resistant tires is a better investment of my money. I have had very good luck with Continental Gatorskins and am currently experimenting with Serfas Seca tires on another bike.

One other handy item in dealing with flats is a pair of tire savers (aka flint catchers or sticker flickers) This is a 1970s old school solution that one can still find on occasion. They work by having a loop of wire in contact with the tire surface and scraping off any foreign objects before they can work their way into the tire carcass. Using tire savers has significantly reduced flats on the bikes I use it on. One drawback is that they can not be mounted on some of the modern bikes with recessed brake mounting and low clearance on the brake calipers.