Sorry for reopening an old thread but norway spruce is the common English name for picea abies, that is the spruce common over most of Europe. The alpine spruce (picea alpestris) and the siberian spruce (picea obovata) are sometimes regarded as a separate species but it seems more and more biologists agree they should be classified just as variants of norway spruce. The three interbreed quite easily and as tonewoods I believe they are regarded as hundred percent interchangable.
Red spruce or adirondack (picea rubens) is native to much of the USA and closely related to norway spruce. It seems most guitar makers regard it as equal to European spruce while violin makers tend to not like it. My personal experience is that a red spruce top tend to produce a brighter tone than one made from norway spruce. Not better or worse, just different.
Sitka spruce (picea sitchensis) is a distant relative to red spruce, native to Canada and Alaska, that has been commonly used for tonewood the last few decades. The tonal characteristics are very different from the spruce variants traditionally used as tonewood.
If you haven't got an ego that is bigger than the world, forget it and let the music speak! (Pepe Romero)