Well, in my opinion, in 06 Mr O, his legs are looking bigger/fuller from the front, a better sweep. As far as condition, he's drier in 06, but i think overall cond. is better in 07 ASC. To pick an overall winner from all those 3 years, i'd say 07 ASC, but in 06 he looks very good too.
...but one more thing, the pics from 07 Olympia are not scaled right, he's appearing to be smaller, a bit narrowed in some pics (look at 06 O vs 07 O most muscular pose and 07 ASC vs 07 O side chest pose), don't get me wrong, it's not your fault, some pics cannot be scaled right because of their angles/positioning faced to the camera..etc, but still you did a great job on this comparison DA, thx!
Front double bicep - 2007 Olympia
Front lat spread - 2007 Arnold
Side chest - 2006 Olympia
Side tricep - 2007 Arnold
Rear Double Bicep - 2007 Olympia
Rear Lat spread - 2007 Arnold
Most Muscular - 2007 Olympia
Abs & Thighs - 2007 Olympia