Wow -- so going to your LBS is a two-week excursion.. I can see why online shopping works for you.

j/k

Here's what I do --

I have two different seat bags, one larger than the other. The bigger one holds what I'd need to change a flat on the mountain bike -- spare 26"x2" MTB tube, that Air Chuck SL mentioned earlier, tire levers, two cartridges, and a patch kit and Presta-to-Schrader adapter "just in case." The smaller bag holds the same things except that the tube is a smaller size for my road bikes.

I also have a Topeak Road Morph G pump that I leave mounted on the bad weather/commuter bike. It's also just small enough that I could easily pack it (and another tube or two) on a really long ride.

I've used CO2 twice so far. The first time was a flat just two blocks from home -- I was returning home anyway, so I decided to use it as practice when I changed the tube at home. The other flat was this past week, riding from home to my LBS (1.2 miles away ).

I've used the Road Morph a couple times, the last time to help out some guy who needed some air in a tire. I use the floor pump every few days, usually just topping off the tires on whichever bike I'm going to use that day.

Here's the catch: I'm never far from civilization. If I have a really bad day of flats and run out of CO2 cartridges, tubes, and patches, I can call a cab to take me home or to a subway station. I also try to use tires that are reputed to have good flat protection (replaced some OEM tires with Serfas Seca on one bike, scored some Schwalbe Marathon Plus off of Craigslist for the commuter), hopefully reducing the chances of getting a flat in the first place.

Get whatever you want; just understand the drawbacks of each. CO2 can leave you stranded after just two flats, but even a frame pump won't help if you run out of patches to repair your last tube. I have to admit, though -- after pumping many tires over the years by hand, the first time I shot CO2 into a tire made me laugh with glee.