A decent case that I could fit about 6 hard drives

Coolermaster Stacker.
Can hold 1 or 2 PSU's and up to 11 drives or cd roms.

It also is about the best case for keeping the parts inside it cool.

Coolermaster also makes smaller cases rangeing from $43-150.

When it comes to a PSU do not skimp with so called "deals". Use a PC P&C PSU even if the buying price is two times any other so called "really good" units (Antec/OCZ ect,ect.). The 510 is far better and longer lasting than most 600-700 units by other "name" companys.

2nd pick would be a Silverstone Zeus.

Cooler Master Stacker

Assuming you are putting in large capacity drives like six 500GB, you will need a good amount of power on the 12v rails. The following is how I estimate power consumption of various hard drive capacities when reading or writing:

500GB...................................40w
400GB...................................35w
300GB...................................30w
250GB...................................25w
WD 74GB Raptor (10k RPM)...40w

It's unlikely that all drives will be working at the same time, but I estimate six 500GB HDDs will consume 240w on the 12v rail by themselves in the worst case scenario.

In this case I would recommend a PSU with 32 amps on the 12v rails like the:

Enermax Liberty 500w PSU

Seasonic S12 500w PSU

Antec NeoHE 550w PSU

32 amps X 12v = 384w

I would say allow 40 watts for each drive when the computer first boots (drive spin up). After they are all up to RPM the pwr draw drops to about 16 watts each.

Some MB's will let you set the spin-up delay time in the bios.

The longest HD/CPU and over all computer life is found by trying to NEVER turn it off,both from pwr draw and heating/cooling cracks in the IC's.

The reason why I want that many hard drives is because the church works under a budget so I can't go all out and spend $3,000 on a system I would have to wait and keep improving as time goes on.
I picked this for a case
http://www.newegg.com/Product/Product.asp?item=N82E1681...