
Yeah the Rad8500 cards are very good and in the US and Canada where they are very well priced they are good bargains. However they do taper out whereas GF4TI cards continue to improve with the fastest CPUs. The Rad8500 isn't hugely slower than GF4TI4200 but the Rad8500 hardly o/c's at all while the 4200 cards o/c to 4400 or 4600 speeds, and that is quite a diff.
BFG10K I rem you saying that Rad8500 with the latest drivers can beat the GF4TI4600, I'd like to some proof of that. Rad8500 is a good card but lets keep things in perspective.

DVD quality on any moderately recent CPU (600mhz+) is largely irrelevant and it's certainly not a huge priority for the vast majority of consumers anyway. As for Aniso although Rad8500 take half the hit of GF3/GF4TI ther quality is noticably inferior, even Rad8500 with 16tap Aniso is largely inferior to GF3/GF4TI's 2xAniso. If you like Aniso or AA (something the Rad8500 REALLY sucks at) then GF3 or GF4TI are certainly the ways to go, unless you can afford the magnificent Rad9700 that is!

As for 128MB vs 64MB. It is only the GF4TI4200 cards which tend to differ in clock speeds and RAM type used, even then the lower clocked, slower RAM and lower o/c'ed 4200-128MB is definitely the better buy. Some current games and most new games will hit 64MB cards VERY hard and it is not a good compromise to make when buying a new card. Just as an example in the current game Commanche4 a 4200-64MB clocked at 300/600 only gives perf equal to a 4200-128MB at STOCK speed (250/444) and nearly all 4200-128MB reach 300/550 type speeds making them MUCH faster than 4200-64MB. Even when taking the standard clocks in to account the 4200-64MB at 250/500 is only 2-3% faster than 4200-128MB at 250/444 despite the 13% extra RAM speed. When a 4200-128MB is clocked to 250/500 (4200-64MB speeds) it gains more than 10% perf. Radeon cards gain even more with 128MB which is evident with the Rad8500LE-128MB equalling the Rad8500 64MB despite the LE being clocked 10% LOWER in both core and RAM! 64MB really makes no sense on a new card unless you have to settle for the likes of GF4MX or Rad7500/9000. Here's alink outlining the diffs between 128MB and 64MB:
AnAndTech 4200 64MB vs 128MB