Uh, the X700XT pretty much ties the 6600GT, of course it doesn't exist. The X700 Pro is slower, but has more memory (which will probably be moot, since it will likely be a pretty slow card before the 256MB memory plays to any big advantage), and that card costs the same as an 6600GT. The X700 isn't even in the same league as the 6600GT. What the X700 does beat up on is the 6600, due to the huge amound of crippling nvidia did to its maistream part (it runs at about 50-60% of 6600GT speeds, as opposed to the X700, which runs at like 80-85% of the X700XT speeds). That's probably what you are referring to.
Anyways, AGP will still be around for a while, but it's gonna be mostly leftovers. ATI and nVidia are basically making sure that the best values will be on PCIe in order to make it more attractive. This is why 6600GT and X700XT/Pro are PCIe only (except for the 6600GT, which was just released on AGP), and future products like ATI's X850XT PE/XT/Pro and the X800/X800XL and NV41 will all be PCIe only. Also, ATI has said that they have no plans to make any of these new cards or the X700 ones in AGP form. Hell, even the best entry level (6200) is PCIe only. The main hardware on AGP will be leftovers from this generation on clearance, with occasional AGP new releases, which will come several months behind their PCIe counterparts and will be substantially more expensive (just like 6800/X800 series PCIe cards are now). Basically, look at the situation with PCI cards over the last few years, and imagine that the AGP situation will not be much different.