if they scale as well at the 6870's i would say so, i remember for a while there 2 6870's was the money. of course u have to take into account crossfire issues so someone might not agree that any crossfire setup is best bang for buck
Honorable Mentions over $400:
Assorted Multi-Card Configurations
The GTX 670 delivers such impressive performance under $400 that we find it hard to recommend higher-performing (but sometimes-inconsistent) multi-card configurations for more money. We'll call out some of the most promising options, though, especially for folks with one of these cards already installed: two Radeon HD 7850s in CrossFire for $410, two Radeon HD 7870s in CrossFire for $520, and finally, two GeForce GTX 670s in SLI for $760.
AMD's current pricing performance ratio unbeatable right now
hmmm is that chart is accurate then maybe a 7950 or 7970 would be better it cost only 10bucks more the the 7870
oh nvm was looking at 7970's crossfired. so yea i guess it is the best bang for buck 2x 7870's
i did not give a definitive answer because you seemed to know what you wanted and just presented some info; though i do not give 100% credence to TT 100% of the time; i really think you are on to something.
7870 CF being the "best bang for the buck" i don't know but i would not be surprised if it is. i'd suggest going for it, i doubt you will be dissatisfied.