I am going to keep this post short and sweet. Here is my pick of hardware, (What I feel is the best bang for your buck) for a home server. I will put together a $400 base build and I will list some extra's you might want to pick up if you have the cash..

CASE $30: APEX PC-389-C Black Steel ATX (no frills case, had to go cheap... but there is plenty of room for modest upgrades down the road...)

PSU $40:  Rosewill Stallion Series RD400-2-SB 400W (400w may not seem like a lot but this should handle our system just fine. You could even upgrade to a middle-weight graphics card down the road and be ok)