Pump; they take more effort by they always get the job done. If I hadn't learned how to cuss as a kid I would have certainly picked up on some choice words watching folks fiddle with CO2 cartridges over the years.
Blackburn FP-1 is my particular favorite: steamlined look on the frame, high-pressure is relatively easy to achieve, and the flip-out T-handle is a nice touch. They also seem to be a bit more resistant to rust than say the Zephal HP's, of which I've had a few. The last one is a keepsake since it was painted to match my single road bike.
Last edited by TandemGeek; 01-30-05 at 09:53 PM.