1. Scott Dixon
The driver of the year, no question. Admittedly luck was often on his side, but he was always quick enough that no-one could begrudge even the rain or strategy-assisted wins. He generally needed no help, he was just the class of the field.
Kept Dixon in sight long after all the other big names had faded away, and was the fastest man in the final third of the season. Didn't deserve to beat Dixon to the title, but did deserve more than two wins.
Kept pushing throughout a tough season for Andretti Green Racing, and was normally at least in podium contention even though Ganassi and Penske tended to have the edge. Still driving as well as when he took the 2004 title.