In an absolute, architectural sense, essentially never. A screamingly fast vector processor isn't going to do much for all your x86 code, and never mind all the little housekeeping chores that the CPU does(most of the modern ones include the system RAM controller(s), do a lot of peripheral wrangling, may be the root of the PCIe bus, and so forth).

In a "designing your next gaming build" sense, they largely already have. Unless you are a money-is-no-object-e-penis-must-get-longer type gamer, you can generally get better bang for your buck by going with a cheaper CPU and spending the savings on a nicer graphics card. It depends on the game, and there are situations where a truly epic(2x or 3x of the top of the line GPU ganged together with SLI or crossfire) graphics system will be CPU bound without the best CPU available; but Joe Gamer is, most of the time, better off with a third tier CPU and a second tier GPU, or a 2nd tier CPU and a 1st tier GPU.

In smaller systems(where board footprint really counts) or in cheap systems(where package costs and board size really count) the integration of CPU and GPU into a single package proceed apace, with AMD rolling low-end ATI tech into certain of their newer parts, and Intel trying to make their GMA stuff suck less. The only real wild card is Nvidia: Unlike Intel or AMD, they have no x86 cores to speak of, on the other hand, their GPU-computing initiatives are arguably the most advanced, in terms of tool and driver maturity. The question is, will they eventually produce an Nvidia equivalent to AMD and Intel's CPU/GPU combo packages(perhaps by buying VIA, who has adequate-but-deeply-unexciting x86 assets; but utter shit GPUs), or will they persist purely as a maker of high end gaming GPUs and GPU-based compute cards?

Unless the heriditary line of the "PC" as we know it is wholly extinguished, there will always be an x86 CPU floating around somewhere in the block diagram(and, in other types of systems, likely an ARM CPU); but it is already the case that, for many applications, the CPU has gotten fast enough to hit diminishing returns for many applications, and the GPU(or just the embedded h.264 decoder) is where the action is.

Yeah, I'd assume that it is somewhere around the time that integrated circuits hit the street. 3 billion discretes, especially with what transistors used to cost, seems a touch unlikely; but it cannot have been long after the integrated stuff became available.

To those rating me as troll:

From TFA:
Unigine Heaven Benchmark v2.0: 18% better
580: 879
480: 742

Quake war: 14% better
580: 176 FPS
480: 154 FPS

Farcry2: 14% better
580: 109 FPS
480: 95 FPS

Alien vs Predator: 16% better
580: 43 FPS
480: 37 FPS

...

Power consumption: 96% of that of the 480
580: 377
480: 392

Woot, 15% increase in performance for same consumption ! Clearly the 580 is "as its name suggests, it's a next-gen product".
If you mean same-gen as the 480, right. If you mean next-gen compared to the 480, clearly not.

They are definitely releasing Tegra-branded ARM SoCs that include their own GPU tech as one of the functional blocks. If that is what you mean by "hybrid", then yes.

To the best of my knowledge, though, neither Nvidia, with their ARM SoCs, nor Intel with their on-package GMAs, nor AMD with their upcoming on-die ATI tech are creating what you might call a full "hybrid"(ie. a CPU whose instruction set also includes GPU-esque instructions, like MMX or SSE on steroids). At present, they are all just more heavily integrating, for economic and latency reasons, a discrete "CPU" block and a discrete "GPU" block.

According to this [overclockersclub.com] graph the difference at idle is almost 90W, or a difference of $180 over 2 years if you leave your PC on 24x7. And I was talking about during the summer, where the added BTU's are paid for in power draw and then again in AC draw.

P.S. My furnace is 93%/16 SEER and my house is only 1200sq ft so in percentage terms it can be a large cost.