As BillyBuerger points out the prices of the "middle cards" have dropped a bit and today you can sort of get $150 performance at $100.
Take a look at the HD4670. That's a card that performs really well (better than the 7600GS in its days) and draws less power than a 7600GS (at idle anyway).
I'll be happy to concede that point. It's hard for me to figure out where any particular card sits on the hierarchy from year to year -- I find enthusiast review sites over-detailed to walk away with, "Will this card play games for the next 2-3 years?" The truth is my AGP 7600GS was able to run Fallout 3, maxing out at well under 150W, and for me that's more than good enough (for now).
The problem with graphics cards today is that neither ATi or nVidia seems to get the power saving features to work correctly. But at least there are power saving features today. A few years ago we had none.
So that's a step forward. I wonder if there's enough market pressure to keep that development advancing.