A good summary WF, time on your hands with no cigs?
Six years ago, ATI were trouncing Nvidia, they ruled the roost. Proving that sometimes Nvidia need a good kick to the rear to make them pull their socks up as they soon regained their lead position.
In my media machine I have a 256Mb Nvidia 7600GT, pefectly good enough for its' needs, I have no intention of changing it.
The other two, well, one's in my sig and I do feel like I've been ripped off a little with the 512Mb 9800GTX as I paid over £200.00 for it and shortly after I purchased it the price came down to it's current asking price of £165.00. No complaints about the card though, it handles everything I throw at it with no hiccups. Have just installed latest Nvidia drivers, V178.13.
The other system is, briefly, Asus M2N-sli Deluxe; AMD Black Edition 6400+ 3.2Ghz dual core; 2Gb DDR2 6400 (OCZ, I think); and a BFG Nvidia 8800GTS 640Mb I purchased way back in Nov '06. That card handles all my games as well, most at full res, though frame rates are slightly lower than what the 9800GTX can achieve. It also won't run Crysis smoothly at a high res, but the 9800GTX will.
If I were in the market now I'd seriously consider an ATI 4870, it's a bargain. Only thing that puts me off is having to rely on Microsft's NET Framework add-on software to enable the Catalyst Centre and yes, compared to Nvidia's current drivers, I do read they are a bit flakey but I don't know as I have no experience of them.
I wouldn't consider an ATI card for a Linux system either, I get the impression, from reading around, that ATI only supply a very basic set of drivers - and only then after public pressure - and those drivers aren't very good at all, particularly for games within Linux.