This is a great list.
My only gripe - see if you can throw in the factory overclocked versions of some of these cards.
I mean, they sell with complete lifetime warranties and perform way better than the stock cards, so they're like a different card in themselves.
Here's an example: Consider a chap who would never overclock a device himself.
He can shell out x$ for a gtx260 or z$ for a gtx280.
Now there are factory overclocked gtx260 which performs very close to a stock 280 but sells for y$, where y>x, but y<<z.
Hope you make sense out of this!