Though to be fair, ATI has always been just as confusing at times. The x1900 line included pro, xt, xtx, and gt came out last even though it wasn't as good. And then they came out with the x1950 line with all 4 as well. If you include the all in wonder, they had 9 19x0 cards. And then some x1800gto's were basically the same as a x1900, similar to the x800gto and x800gto2. Not to mention that 9800s lagged the 9800s sometimes and the 9500s were better than the 9600s, etc. And now you have 3850/3870, 3650/3670 and 3450/3470 lines. I doubt many people know the performance levels of those 6 lines. So is a $80 ddr2 3650 better than a $65 gddr3 3470?
EDIT: They also had gto for the x1900 line so that makes 10 cards in that line.
The 8800s: gs, gt 256mb, gt 512mb, gt 1gb, gts 320mb, gts 640mb, gts 512mb, gts 1gb, gtx, ultra. That makes 10 cards. Though it's somewhat less confusing since some of them are just repeats with different amounts of ram.