Good (and Frequently Asked) Question.
Basically there are four different things to decide: key, wood, fingering, and number of drones. They are (almost) independent.
For this, I would not advice a hard wood (say, grenadillo) for a D chanter, for the D chanter is bright enough on its own. Violet wood, rose wood, boxwood are possible more adequate. A C chanter is a little bit sweeter than a D one, and so grenadillo (plus any of the aforementioned woods) is a also a good choice for that. And finally, what one wants for a Bb or A chanter is usually a mellow sound, so a light wood would be advisable -- but if you want for whatever reason play with other instruments in A or Bb, and you want a prominent sound, go for a harder wood. Usually (but not necessarily: you can order special combinations) the whole bagpipe is made of the same wood.