I really am not interested in a next-gen Xbox and PS4 if they're only going to offer modest improvements on what 360/PS3 do today. IMO, having current-gen like graphics at 1080p, with more AA, sharper textures and somewhat better framerates won't be enough. I'd rather wait until they can do more CG-like graphics, regardless of resolution (720p or 1080p).
There was only 4 and 5 years from the release of original Xbox1 to the release of Xbox 360 and PS3. Next time it should be 6 years from the release of 360 and PS3 to Xbox Next and PS4, in 2011/2012, allowing for a larger jump in graphics. The CPUs do not need to be increased massively from the current Xenon and CELL. A 2x to 4x increase would be fine, but graphics could increase 10 to 20 times, given that high-end PC graphics are already 4-5x beyond console graphics (looking at single GPUs nevermind SLI and CrossFire).
Having much more powerful GPUs in next-gen consoles does not mean they have to be expensive. They could still launch at $299 for a basic SKU and $399 for the SKU with all the bells & whistles, and there would be NO $499~ $599 SKUs at all, like there where this gen. Blu-ray will be dirt cheap by 2011/2012. Sony has already made the investment in CELL, and will probably go with a 16-32 SPE version of CELL. Microsoft will go to Blu-ray, and probably a 6-12 core version of Xenon.
I don't know if a HDD will be standard or not. Maybe not in a $299 Xbox Next/PS4 SKU.
Next-gen consoles will focus around reasonable price, new control interfaces, greatly expanded online network and services, impressive 'next-gen' looking graphics, but not go overboard on totally new CPU architecture which was partly responsible for jacking up PS3 price.
I think Nintendo will once again be behind Microsoft and Sony in terms of hardware, but not as massively so with Wii compared to 360/PS3. I think the Xbox Next, Wii HD and PS4 will all seem to be of the same generation. I also think that by fall 2012, all the next-gen consoles will have launched, and that current-gen consoles will be around until 2014-2015, three to four years into the next cycle.