I always had/have a server at home serving our basic IT needs like Email, Web and file sharing. I do have a very powerful one, an IBM Netfinity M20 5500 with 4 CPUs, RAID 5 SCSI disks, etc, but I found it a bit overkill for our needs at home, and the electricity bill did nothing but backed my statement up. Therefore I was out (out = googling) on a hunt for a small and silent, energy efficient server. I found several types and kinds, but the one I settled for I believe serves our needs perfectly with a barely noticable 11W/h energy hunger.
Read on for details….
This little guy is called Microclient JR, and it comes from NorhTec, a company based in Thailand. The device itself is a generic device, and its sold under the name Ebox 2300, and some more. The specs are the following:
x86 compatible processor
128 MB RAM
Tiny footprint
VESA standard - mount to any LCD
No cooling fan or moving parts
Regular expansion ports - USB/Serial/LAN etc.
The cost for this little guy is just $120USD currently, and can be purchased at:
http://www.norhtec.com/products/mcjr/index.html
I got the minimum setup without the extra COM ports and no WiFi antenna either. If I had wanted any of those features, I would be left with no space for a HDD in the belly of this little guy. The server itself is really tiny, a laptop HDD at 2’5″ barely fits inside.
Of course we need to keep in mind its limitations, like the 128MB RAM, which isn’t expandible and the fact it has a very slow CPU. Given all these facts, its still able to handle a basic Debian installation, and the following services are running smooth on it: Exim4 for emails, Courier POP, Courier POP-SSL, Courier IMAP, Courier IMAP-SSL, Apache2, MySQL, Squid Proxy, SAMBA, ProFTPD and of course SSH.
I ended up putting an 80GB Haddisk in it, as I needed some more memory in cases of heavy load, and if I set up a SWAP partition on an otherwise available CF card, it’s silicon (I guess) cells will die off quickly, and I will end up replacing it way too often. Any memory card has a maximum number of write cycles, and once it reaches it, things turn mad. At this moment, the little guy uses about 90MBs of RAM, and in extreme situations, when it for example does the daily Squid Proxy report, or checks multiple messages for SPAM and viruses, the RAM usage jumps to 140-150MB. At those times, the extra 256MB SWAP I had set on the HDD comes handy. If I leave the guy with a CF card and no SWAP, it will crash at times of overloading.
Finally, here are some pictures to wet your appetite
And here it is set up at home, with a Cisco 806 router and an Apple Extreme Base Station 802.11n Wifi Access Point. You can see that Junior beats them sizewise anyday 
Cheers