Already discussed at length here on HN as well and especially r/homelab et. al., algolia search to the rescue:

https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...

http://www.reddit.com/r/homelab/

http://www.reddit.com/r/HomeNetworking/

http://www.reddit.com/r/HomeServer/

https://forums.servethehome.com/index.php

Good luck! Rackmount machines are their own world. Done right they last longer than desktops with the added benefit of typically being quite loud. Stay cool. B-)