1.) Make sure to get a Z87 motherboard without the USB 3.0 bug (you want a chipset with stepping C2 and revision 5). Get that in writing before you order your motherboard!
2.) Make sure you get a motherboard with at least a display port on it. A Thunderbolt connector is also highly recommended.
3.) Get a massive CPU cooler, if you haven’t one already. A water cooling kit is a must have for people who plan to overclock their K model CPU.
4.) Check for UEFI BIOS upgrades regularly and install them when available.
6.) Get a motherboard with Intel LAN.
7.) Get a motherboard with a supported codec (892/898) so that you’ll have audio from day one.
8.) Don’t expect power management to work without a UEFI BIOS mod. Yes. MSR 0xE2 is still locked and thus your UEFI BIOS need a patch, but since it is essentially the same kind of mod that we have been using ever since Sam figured it out… this is not a problem.
9.) All power related tests out on the Internet are VOID in the world of Apple/OS X – I have no idea where these people are getting their data from, but what I can tell you is that my 2500 Euro hardware shows me anything but the wattage they publish in their tests.
10.) But most importantly… wait for new Apple hardware with OS X 10.9 pre-installed on it 😉