This would
not be a suggestion for your NL box, just want to share an experience ... I just recently picked up a refurbished Dell with a very modern mobo. (Inspiron 530 desktop.)
First surprise: **NO** IDE ports. This means SATA **ONLY**. Which *might* cause a problem with NL if you need an optical drive (does not apply to the USB version ... the USB stick can be formatted on a different PC), because I think I read that SATA optical drives might be unsupported in NL (someone else can confirm this ??) unless the BIOS supports an IDE legacy mode.
Second surprise: **NO** 4 pin Molex power connectors. This means I can't even used a spare standard IDE DVD-RAM/RW drive via an IDE-to-USB or IDE-to-SATA converter, unless I modify the Dell power supply. (This concern won't apply to you at all, since you are hand-picking the PSU.)
Third surprise: The intel G33 chipset. Trying to use my Acronis True Image 9. And I think Acronis uses a linux kernel like NL. Using the FULL version of Acronis TI recognizes *NO* hard disks !!
Anyway ... older (let's say "well-established" ... "been-around-for-a-while") mobo ... will save you money, and may be these kind of troubles.
Don't fret too much, but use the feedback from previous posts ... my NL experiences are all on Intel socket 478 mobos from various vendors and very few issues -- all of them solved.
I think you're on the right track ... have fun with it.

Georg