I really like the pump that my not-quite-lbs put on the tandem they built for me. It's a Topeak Road Morph G Master Blaster. It mounts on water bottle braze-ons and has a pressure gauge built in. The mount is quite secure, which is important to my paranoid side. Here's one on Amazon: http://www.amazon.com/Topeak-Road-Mo.../dp/B000FI6YOS

I'm a bit of a retro-grouch. I still ride an old steel bike and I have never used CO2 cartridges, just pumps.