Taking speed as an issue it may be better to choose another language, but, what is your library/module/implementation of choice for doing 1D FFT in python?
I would recommend using the FFTW library ("the fastest Fourier transform in the West"). The FFTW download page states that Python wrappers exist, but the link is broken. A Google search turned up Python FFTW, which provides Python bindings to FFTW3.
I would recommend numpy library, I not sure if it's the fastest implementation that exist but but surely it's one of best scientific module on the "market".
FFTW would probably be the fastest implementation, if you can find a python binding that actually works.
The easiest thing to use is certainly scipy.fft, though. Plus, you get all the power of numpy/scipy to go along with it.
I've only used it for a toy project (a basic music visualization) but it was fast enough to process bog standard audio at 44khz at 60fps, as far as I can remember.