Okay, first I'll do my own calculations.
According to the ADTOE booklet:
Music by:On the Backs of Angels: Petrucci (33%), Rudess (33%), Myung (33%)
BMU, BMD: Petrucci (25%), Rudess(25%), Myung(25%), Labrie (25%)
LNF: Petrucci(25%), Rudess(25%), Myung(25%), Labrie(25%)
This is the Life: Petrucci(50%), Rudess(50%)
Bridges in the Sky: Petrucci(33%), Rudess(33%), Myung(33%)
Outcry: Petrucci (33%), Rudess (33%), Myung(33%)
Far From Heaven: Petrucci(33%), Rudess(33%), Labrie(33%)
Breaking All Illusions: Petrucci(33%), Rudess(33%), Myung(33%)
Beneath the Surface: Petrucci (100%)
So, average each member's performance we get this:
album averagePetrucci = 40 percent
Rudess= 30 percent
Myung= 20 percent
LaBrie= 10 percent
Mangini= 0 percent
I'd say the above chart of averages represents pretty what I've always thought about the band pretty well. I suspect most of you guys think Mangini contributed in some way-- I'm sure he did things here and there, but ultimately not enough to actually be given any credit as a writer. So, we still haven't seen Mangini write with the band yet and that's where I disagree with your poll. I mean, I'm sure he made adjustments to John's outline here and there, but he himself has been very clear about what a miniscule role he's played in the writing process thus far.
Since I can't vote him down, though, I just voted Myung up. He seems a bit under-represented in yours!
Phew. I haven't done that much math since like highschool