1. A medical diagnostic ultrasound system comprising: a plurality of subsystems along an ultrasound data processing path including a beamformer subsystem, a Doppler processor subsystem, an RF processor subsystem, and a scan converter subsystem; wherein one of the subsystems has an essential data processing functionality, the essential data processing functionality including data processing of ultrasound data, the essential data processing functionality of the subsystem largely residing in at least one but less than three reprogrammable logic device components; wherein for the beamformer subsystem, the essential data processing functionality comprises filtering, interpolating, demodulating, phasing, apodization, delaying, summing or combinations thereof; wherein for the Doppler processor subsystem, the essential data processing functionality comprises clutter filtering, auto-correlation, estimating velocity variance, or energy, or combinations thereof; wherein for the RF processor subsystem, the essential data processing functionality comprises detecting an envelope, amplitude or power, log compressing or combinations thereof; and wherein for the scan converter subsystem, the essential data processing functionality comprises interpolation.