Do you want PCI-express? If you do you have to go NF4.
I'm waiting another week or two before I order my new system for more NF4 boards to come out, since I want PCI-express graphics. I don't game much, but may start to play more now that I have more time. If I need a better card, PCI-E will be a lot more upgrade options in the future, or if the 6600gt is good enough for me for a long time, I'l be able to put it in my next system. By the time I need more processing horsepower AGP will probably be totally gone. Either way PCI-E is more flexable for the future, and the (native, like the 6600gt)PCI-E graphics cards are usually a little cheaper than the AGP bridged ones, while an NF4 motherboard doesn't cost a whole lot more than an NF3. So unless you have an AGP graphics card you want to use, or want one that is only out in AGP form, go for NF4.