One thing to point out: a purple (JasonN) or yellow (MagnoliaFan) blade is much easier to pull off than a green one, because any remnants of red will stand out a lot more if you try to make it green, red being the opposite of green but a component of purple and yellow. Myself, I'd go for yellow, but that may simply be because I saw MF's edit first.

I also think it would be interesting to see a much greater range of colours for the Jedi, rather than uniform blue and green — have each sabre a slightly different shade of blue or green, maybe even ranging from purple at one end to yellow at the other. Of course, this would be very difficult and time-consuming for any editor. It depends on whether we want to paint the Jedi as individualistic and free (in which case the more variation the better), or dogmatic and ordered (in which case the less the better).