Look, the R9 series are based on the 7xxx chips, just like the re-branded 8xxx series. The difference is that they are better optimized since the 20nm production process still didn't reach stable if I recall correctly. As for R9 290X, it won't be a re-made Southern Islands, it's a new architecture. And when you think about it, these new R9 chips are cheaper than the similarly-performing 7xxx series, meaning these have a better price/performance ratio. That might not mean much to someone buying a 1000$ card, but it means a lot to a bunch of people, me included.
It seems to me like AMD didn't pull the performance up and smack a hell of a price-tag on those, instead they slightly boosted the performance of the old series and sell them cheaper as new series, which business-wise, is a really good move. This way instead of selling 10 500$ cards, you sell 20 300$ cards, 5000$ < 6000$ is a simple math. This will only rile up the fanboys and uber-performance seeking guys, but I care little about them, they got their Titans, 690s and 7990s, but guys on a budget will be happy with R9s.
And the title of this thread is "best cards", but the term "best" is subjective to views. For me, best means a cheap card that performs well, for you it means the best performing single-card, regardless of money. As I already told you, the fastest single-card solutions are the Radeon 7990 and GTX 690 (dual-chip single cards) or GTX Titan and GTX 780 (single-chip cards). R9s are re-branded budget solutions and you can't compare them to the GTX 780/Titan which are derived from the latest line of Nvidia workstation chips (Tesla) and cost 2-3x more than R9s.
EDIT: Now that I think about it, I'd wait if I were you. If you''re determined to get an Nvidia card, wait, with the R9 series coming out cheap it may be enough for Nvidia to drop prices in order to stay competitive, which means they might just drop the 780s price as well. I can smell the price drops, but my sense of smell fools me occasionally so it might be a dud. 
Edited by Werne, 11 October 2013 - 10:47 AM.