I have a Topeak Mini Morph that I've been using since 2008. Every so often I disassemble it and re-lubricate the pump. It's been moved from my road bike to my hybrid, but it still serves me just fine on the hybrid.

I have a Lezyne Road Pump on my road bike. It's fine too. For usability I prefer the form factor of the Topeak Mini Morph (any of its "morph" siblings would be fine, too). For sleek looks, the Lezyne has it.

CO2 is fine if you never get more than two flats on a ride. In goathead territory that's not necessarily a foregone conclusion. I do bring CO2 along once in awhile, but I'm always reluctant to leave the pump behind. It has an unlimited supply of refills built in. With the CO2, my first flat will be turn-around time because having only a single cartridge in reserve is living too dangerously, for me. I can go weeks at a time with no flats, but I've had as many as five on a single ride.