cpu load when playing audio from sd-card

I'm searching for a versatile Cortex Mx-board to develop projects until i can create an own board for it.
The Arduino due would be nice because - as far as i know - it's easy to get help on the internet...

How much capacity will it take to read 16bit stereo wave from a sd-card and put it out through a DAC? (This is the most cpu-intense task i can imagine for now)

A few more questions:
*how difficult is it to get tricky things like SD-Cards working?
*how relieable is the programmer? (Some other ARM-Boards have really unstable on-board-programmers)

Well, 16 * 2 * 44100 = 1,411,200 bits per second.
Plus SD card overhead.
8-bit, 16 MHz processor can do single channel read from SD and send to DAC.

Some thingmore than twice as fast should have no problem.

SD card is not hard with a good library. fat16lib writes good libraries, google his sdfat.h library and see if it wiorks on Due.
Due programming from IDE seems pretty stable.

I am working on a project right now doing exactly this on my Arduino Due board.

The Due can definitely play WAV files from SD card. And the sound quality is remarkably good. However, I was experiencing some small issues. See Arduino Due Audio library have some small bugs - Suggestions for the Arduino Project - Arduino Forum