Repurposing gaming rig to server

[Cottonwood00]

So I plan on building a new computer in a little but I'd hate to waste my old hardware so I plan to repurpose my old system into a server. The questions I have are mainly on configurations and software.

The current system off the top of my head:
1. AMD Phenom II X4 965
2. 12gb G.skillz something
3. 2x 640gb HDD
4. 60gb Crucial SSD (OS)
5. 1x 300gb HDD
6. (some video card) ill just remove to be headless

I'll edit when i get home to be more accurate but anyways I have a few things Im looking to do.
1. Run Virtual machines for my dev lab (web server, db, git, utilities) each very small
2. Run plex media server for all my media needs(need transcoding)
3. I'd like to setup raid (maybe buy 3x 2tb drives) to consolidate my media into a single raid pool and get some parity
4. uTorrent and what have you.

I'd prefer to use a nix OS but im ok with freeBSD anways im interested in your opinions as to what software you use such as OS's, server management, raid managment, VM software.
Also interested in the type of RAID array you'd use for media storage.

 

[plugwash]

6. (some video card) ill just remove to be headless

Note that PCs generally need some form of graphics to boot. So if the board doesn't have onboard graphics you may need to keep the graphics card (or replace it with a lower power one).

 

[Dangman]

What case, PSU, and motherboard do you have?

From the many planned VMs you're running, I'd look at ESXi or Xen for your virtualization needs. That way you won't have to rely on a host OS at all for your virtual machines and you will get better performance per VM. The Virtualization FAQ in the Virtualization subforum is a good primer:
http://hardforum.com/showthread.php?t=1366895

As for the storage, this is probably going to be one aspect of the server that's going to take you the longest to figure out. There's a lot of different storage setups out there and there isn't one that stands above and beyond the rest. Just a few off the top of my head:
- Drive Bender
- Stablebit DrivePool
- SnapRAID
- FlexRAID
- Linux MDADM RAID
- unRAID
- Openfiler
- ZFS (which can be used with FreeBSD, ZFSguru, FreeNAS or Solaris IIRC)
- OpenIndiana with Napp-it plugin

Though if you want somewhere to start, look at ZFS. It's a fairly popular storage platform over in the Data Storage subforum and does have a lot of features that would certainly make it one of the prime candidates for top storage platform. But it does have some caveats that you'll see once you do your research that prevents it from being the top though.