Gigabyte's new Canterwood-based GA-8KNXP is, without a doubt, one of the most full-featured motherboards we've ever seen.
It incorporates all of the basics offered by the MSI 865PE Neo2 (see below) plus more. The differences between the older 845 and new 865 (Springdale) and 875 (Canterwood) chipsets are primarily feature-based – the 875P is designed to be the ultra-high-end option for extreme power users. As such, it's more expensive but has more niche capabilities.

What really marks this from its competitors is a capacity for unparalleled storage. With two SCSI, two SATA and four IDE ports, you can plug a lot of hard drives into this puppy. Also equipped with six DDR-RAM slots, an AGP Pro for use with special high-end graphics cards, it includes a second power array (known as Dual Power Supply) helping reduce the strain high-end components put on the power grid. In some ways, the 8KNXP is more suited to running as a graphics workstation or server than a high-end desktop; even power-users will likely find that many of its capabilities would be wasted.
The one notable feature the 8KNXP lacks is FireWire, a rather conspicuous exclusion considering the high-end nature of the board.

Performance with the 8KNXP is excellent. But like MSI's 865PE, it doesn't excel above and beyond existing 845-based P4 boards unless you're using the latest and greatest technologies.

While many of the features are niche, Gigabyte has done an excellent job integrating them. If you can use all the high-end features and the extra storage options, or simply want a P4 board with integrated SCSI, then the 8KNXP is an admirable choice.