Building a new household server....

Like a lot of families these days, our household IT infrastructure has had to adapt as we all became more and more fond of computers for work, school and recreation.  With digital photograpy, ripping hundreds of CDs, describing our various activities and travels on web pages,  two teenagers and the heavy use of email, and the need to provide stable storage for homework and digital art, we've been playing catchup for a while.  This led us directly to designing and building a new server to handle storage of all the digital media, web-serving and email.  At the same time, I was tired of the whine from the surplus X1 rack mount server I had stuffed in the closet, and decided to merge my home desktop and server together to reduce power consumption.  With some
thinking we arrived at the following hardware design:

Well, this went together pretty easily (especially since I had my son do all the work...).  The software selection and configuration was actually considerably more effort than picking the hardware components and building the system.  We're now running:

So far things are working very well.  The 4x500 GB drives are in a RAID-Z configuration with ZFS; we can sustain 120 MB/sec or so reading or writing to the 20 odd filesystems configured on the single pool.  Samba works well enough; we managed to feed 10 different files to 10 different clients at nearly 100Mb/sec apiece during one of the kids' Lan parties.  Dovecot in particular seems very fast on top of ZFS.  What are we still thinking about changing? Well: