Originally Posted by: Bucky The maj. 7th is used only for "effect".

Yeah. Also look at the fact that it is playing the role of "leading tone" to the root note that follows it. That's it's function there. If that G# was to resolve down a whole step (F#), it would sound wrong. If G was used instead of G# as the leading tone to A, the musical effect on that sequence would be "weak". The raised 7th is also preffered when using the V7 chord in a minor key. In blues however, the b7 is preffered due to the downish sound of the b7 over the harmony. So the blues minor pent should not be traditionally altered, a raised seventh in such a context is a non-harmonic (chromatic) tone. IMO the raised seventh only sounds right when used at the end of a sequence or cadence as (#)7-1(minor). In rock music I use the raised seventh more than the flat seventh because I prefer the classical approach to rock over the blues approach. Modern rock is just to fast paced to suggest "blues".