siliconfury wrote:I find it depends on the skill of the writer. E and G are quite natural keys to play in on a guitar due to standard tuning. Anything outside of that can be tricky to improvise over without knowing exactly what you're doing, and a lot of the time it'll just end up sounding 'wrong' and you fall back to Emin/Gmaj, or you 'force' the song into that key (which might end up having some accidentals because you haven't transposed the scale properly) and it ends up sounding like shite prog.
http://www.youtube.com/watch?v=3eBfXfWPkGg
I don't know if you'd call this prog (I really don't know what the definition of prog is [also i tend to call it technical thrash/death personally]) but it isn't too dissonant and it's a very good example not having to use a scale at all. Just two notes (can you guess which ones? )