Hello dear readers, here's me coming back for the actual content !
First, (and maybe the most important for some people) the looks. The motherboard looks great. Color coordinated, in shades of blue with the trademark “Asus black” PCB, and its oh-so-characteristic font for model name.
Second, the features. The layout is really good (no IDE or Molex cables going all the way around to plug into the board), a huge number of PCI/PCIe ports (3 x16 physical, 2 x1, and two PCI ports, all with a great layout (x16, x1, x1, x16, PCI, x16, PCI) ensuring optimum airflow for SLI or crossfire as there is an empty slot between the two dual slot cards.
A very interesting thing (that's shows minor details can make quite a difference) is the RAM slots. On a classic motherboard there are two moving “locks” securing the stick, on the slot. On the P7P55D, there is only one lock on the top part, the bottom one is a moving pin/spring that does the job well, while still ensuring a good and snug connection.

Pic from Asus (cropped)
There is a COM header for serial port (in white on the pic), which I miss on the P6T Deluxe as I like to do some debugging or programming microcontrollers and adding a serial to USB makes things a bit more complicated. And for modders it can be a useful thing, because for example what I’d like to do someday is making an analog gauge (that I have, it’s in % and goes from 0 to 110% ) to show CPU usage. One implementation can be outputting the value over serial (thus using the internal COM port) and have it read by a microcontroller to drive the gauge. Instead of jumpers to change to remove the limit on memory/IMC/CPU voltage, Asus has put a nifty switch, resulting in no lost jumpers.
Underneath the lever, where your finger has to push to unlock the CPU socket, there is a small plastic “sticker” part, slightly transparent, that protects the PCB and the traces in case the lever would touch it. You don’t “scratch” the board itself, you just slide on the sticker. This attention to detail is quite a nice touch from ASUS (I didn't see it from the pictures of other manufacturers), to keep the board up and running after many CPU changes...
Just look at the picture !

That's all folks, see you next week (or later during the week) for more content !