European Spruce
Often known by its country of origin, this is generally regarded as the best spruce for classical guitar tops. Now becoming more expensive and difficult to obtain.
Englemann Spruce
This North American wood is now starting to become very popular for classical tops. It is usually slightly less dense than european spruce, with a more even, pale cream colouring, and can produce a slighty mellower sound. There is currently a good supply of high quality wood available.

Western Red Cedar
From North America, this is a very popular wood for classical guitars, being the preferred choice of a number of top makers.
It is softer than spruce, and not as stiff, but good sets have a narrow, straight grain, and a distinctive, clear tap tone. The colour is darker than spruce, ranging from light yellow/orange to darkish brown.

Western Red Cedar is currently in plentiful supply and I have some very high quality sets in stock.