I use Titan Performance plugin for WoW. It captures min, max, and average frame rates. And it uses the same "green is good, red is bad" color coding.
One baseline test we often do is to enter Narache Village in FireTree realm. We take a Warrior and have him run from the Totem pole at the entrance to the village to the large tree at the top of the hill to the East. Then run back to the totem pole. We've found it's a good baseline test of graphics processor speed.
For example, at 1920x1200, 4x Multisampling, all other parameters at max, we average 59 fps on the iMac with GeForce 130 GT. The Mac Pro 2.93 with Radeon 4870 averages 84 fps in the same scenario. The Mac Pro with 120 GT averages 33 fps.
Of course if you were observing or participating in a raid with lots of spells being cast, the frame rate would drop but, again, we're going for repeatable baseline.