I consider GT a system seller. I know many people who are buying PS3/have bought PS1/PS2's only for GT. Some even only bought the GT games and no others. Anyways, GT is a great series, I certainly enjoy it and so do millions. It is always AAA quality. The #'s don't lie.
GT1: 10.85 mil GT2: 9.37 mil GT3: 14.84 mil GT4: 8.02 mil
5
GT1: 10.85 mil
GT2: 9.37 mil
GT3: 14.84 mil
GT4: 8.02 mil
http://www.vgcharts.org/worldtotals.php?name=gran+turismo&console=&publisher=&sort=Total
Halo: 6.44 mil
Halo 2: 7.91 mil
While Halo was on a system with a much smaller userbase, GT had to compete against a system with a lot more games for it.