Watch the Big Blue Groove - Solo online guitar lesson by Jeff Scheetz from Rock Solid
I am going between my E mixolydian mode and my E minor pentatonic scale on this one. The minor pentatonic gives it a blues feel while the mixolydian gives it a dominant feel. Jam bands love the mixolydian scale almost as much as they love tie-dyed-clad twirling fans!
The mixolydian has a great flow to it - and it works great over a 7th chord groove. Check out any jam bands that are playing over a fairly happy groove and chances are you will hear the mixolydian scale.