I should know by now that installing a new motherboard isn't gonna be simple.
I picked out the Asus A7V8X (w/ SATA & Firewire) and an AMD Athlon XP 2600+. Seemed like an awesome combo - until I tried to boot. After much unjoy (no POST or screen), I decided to plug my speakers into the onboard sound to hear what my mobo was saying (yes really - Asus 'Post Reporter'). It was saying 'System failed due to CPU overclocking'. Hardly possible; considering I wasn't.
To make a very loooong story short; apparently my mobo doesn't like my Linksys LNE-100TX NIC (v2). I stuck an old reliable Realtek in and it boots fine. I'm just now getting to test the box and reconfigure stuff (after a day of it being down). I guess it will be faster in the end.