[EDIT: OpenIndiana-discuss concludes that the broadcom network chip is not supported on Solaris, but there is some interest. Also, to use 4 disks as storage, you may have to use the on-motherboard microSD chip, or the optical disk slot, to boot from. I'm using Linux and am very happy with it.]
HP made an amazing new Microserver, the gen8.
Intel. Haswell. Fanless (the CPU at least.) And it's as fast as my old 3GHz one.
It's tiny and holds 4 disks (plus a tiny space for a 5th on top.)
I just turned off the built-in soft RAID.
This is a really good start for a home server. Recommend it.