Actually I think I might start building a new box now in preparation.
As far as a home server or even for a small business scenario I can happily recommend the HP microsrver series, N36L, N40L, N54L and the latest Gen 8.
I have a 40 and a 54, they will take up to 16gb of memory, 4HDs in enclosures, price for 54 from around $250 brand new, although you do get them on specials got mine for $199. Gen 8 start at around $450up depending on the CPU its a bit more serious
but same form factor as the 54.
They are super quiet, low power users and small form factor so fit just about anywhere..
Heres a wiki
http://n40l.wikia.com/wiki/HP_MicroServer_N40L_Wikiand the overclockers users forum
http://forums.overclockers.com.au/showthread.php?t=958208My N40 has SME8 on it runs my home data/media storage etc, 8gbs of RAM
The N54, 16gbs RAM, modded BIOS, runs 5.5 ESXi on a 120GB SSD in the OD bay in a Vantec enclosure with a couple of 500gb drives as datstores, SME8, 9, CentOS 5 and 6, Win XP, 7, Fedora, Vector Linux, not all at once of course, the little server can only do so much, but will run three SME VMS at once without problems.
You may get the impression I am happy with the "toys" I am and of course compatable with SME8 and 9, and so far everything else I have thrown at it.