Wow! Thanks for the responses. I'm glad to know I can learn with circular needles. The part about them being easier on your hands and wrists is a big plus for me.
I plan to make a scarf as my first project. How do you know what length cable to use for flat projects? It seems part of it is preference, but what else do you go by? For example, if I plan to make a scarf that is 8" wide, how much extra cable space is needed?