AMD had announced quad-core before Intel, IIRC.
I know Intel had trouble getting a 4GHz chip to remain stable within certain parameters so they decided to drop that. I have no doubt that if Intel had been able to get a 4GHz or faster CPU within the right parameters, there'd be one out now.
Don't expect to see a Pentium 5. From what I'm understanding, Intel is dropping the Pentium, and eventually, Celeron brands and just going with CPU models 3xx, 5xx, 6xx, 7xx, 9xx. The first number would be the market grade (the 300's would be the Celeron, everything else would be a Pentium-class). The higher the first number, the more features it would have. The higher the last two numbers, the faster the CPU's clockspeed would be.
Time will tell how this bowls over. Everyone thought AMD's PR rating system would be the end of it all, but they've run pretty well with it.
Once websites can do their own internal testing, we'll see how Conroe performs. However, I believe they're taking lessons from their excellent performing mobile chip, Dothan, and moving that to the desktop. The architecture is more effiecient and effective than anything under the Pentium 4 probably has been. Unfortunately, nVidia hasn't officially released a universal SLI driver to work on non-nForce chipsets, and I think if they don't, that could cost them dearly. ATi's Crossfire could use some work, but, unlike SLI, you can run a Crossfire setup on a non ATi-chipset system.