BUILD First proper server build - a modular approach vs. AIO

[ciscam]

Hi!

Half a year ago I recycled my 2005 gaming pc to be a home server. Starting off with Microsoft Server 2012r2, I fell in love with virtualization. As soon as I started to be concerned with storage solutions, though, it became clear that the only awesome and worriless solution is a bare-metal freenas deployment.

After one month of tinkering, though, this damn machine started to randomly freeze, starting at POST.

Show : The old build, fyi

Mainboard MSI K9A2 Platinum
CPU AMD Phenom X4 9850 Black Edition
CPU-Fan Scythe Ninja (no fan)
GPU Sparkle GeForce 9600GT passive
RAM 2x Mushkin 4 GB -- 1x 4 GB random leftover
PSU Corsair CS450M
HDD WD Red 3TB -- Samsung Spinpoint 750 GB & 640 GB -- WD MyBook 3 TB (USB 3.0)
Case NZXT Source 210 Elite with Aerocool DS fans: Front (2x120mm), Back (1x120mm), Bottom (1x120mm), Top (2x140mm)
Boot Kingston Data Traveler USB2.0 16 GB

Went for passive cooling. It's loud as hell and the CPU regularly had 100°C panic shutdowns under load

My definite requirements for the new system are:

• Fulfills freeNAS/NFS standard for data security
  • ECC RAM
  • Preferrably a tested Supermicro board
  • Possibly gimmicks like a built-in UPS (or redundant PSU)
• Can manage ~3 TB worth of data, starting with a WD RED 3 TB mirror
  • This is only going to be synced and remote accessed, should be an IO of about 1 GB per day
• Can run a Ubuntu/XAMPP VM for single user access
• Power efficient to a certain extent

Luxury that I'd really like:

• Plex (only me, in the worst case a maximum of two simultaneous streams)
• Torrent/VPN - which means that I'm gonna need to expand storage sooner or later
• A silent system that I can sleep right next to

Things that might or might not become necessary to me:

• Growing storage
• A production web-server to cover the gap of a project until we can afford outsourcing
• Gadgets like mailserver, irc bouncer, cloud-sync for my android phone - basically every google service one might use

Now, my conclusion was to get this build:

Mainboard Supermicro X10SL7-F
CPU Intel Pentium G3220 - to be xeon'd by demand
CPU-Fan (boxed)
RAM Samsung 8 GB ECC UDIMM - to be expanded by demand
PSU Corsair CS450M
HDD 2x WD Red 3TB (mirror) -- Samsung Spinpoint 750 GB & 640 GB (mirror, just for fun) -- WD MyBook 3 TB (USB 3.0) (backup, until I have the money for additional Reds)
Case NZXT Source 210 Elite with Aerocool DS fans: Front (2x120mm), Back (1x120mm), Bottom (1x120mm), Top (2x140mm)
Boot Kingston Data Traveler USB2.0 16 GB

But right after I ordered mainboard, CPU and RAM, worries befell me.
Even if it's all on a to-be-expanded basis and should still suffice, wouldn't it be a much more viable option to not buy a can-become-megatron machine and instead settle with one that fits my urgend needs, holding 3 TBs of data on a mirror, maybe becoming up to 12 in a RAID-Z2 with the regular 6 drives any board can manage, and running an Ubuntu VM with XMPP?
The latter usage would not need a powerful machine at all. And if any other demands arise, I would rather get a second box, than tinker on with my one-and-only.

What do you think?
Heck, I even thought of something like this:

The freeNAS's boxes only purpose being NFS there.

I'm totally overwhelmed by possibilities and eventualities. Please help me find reasons to eliminate the approaches that are not viable.