HTPC / NAS / FTP all in one box?

Is there a reason why you want it set up as a nas instead of just sharing the drives?

I have a similar setup as you. 10tb server running win 7. I also use it for my torrent client, ftp server, etc. It also feeds media to the other htpc's in the house.

I use software raid. (snapraid). Adding a vm sounds like added complexity for minimal gain. But maybe I'm missing the benefit.

According to Google popcorn hour and apple can both read smb shares. Which is what windows uses. It's not a workgroup the drives are just shared over the network.

I did come across some issue where osx lion uses smb 2.0

I use neither of those devices though so I am not confirming anything. Just giving you some info.

To do an all-in-one, take a look at this: http://hardforum.com/showthread.php?t=1573272 -- That's basically what I'm running.

I don't know how stable it would be running the configuration you've proposed with Win7 as the base OS.

I do something very similar using ESXI5 as the baseline OS with one VM running ZFSGuru to provide ZFS-based storage (Samba, AFP, iSCSI and NFS) to all the other VMs. I even use iSCSI to provide storage to my HTPC clients running small SSD boot drives so they have a drive to record TV. I got my strategy from from the link above, the only difference is that I use ZFSGuru (FreeBSD based) instead of one of the Solaris derivatives.

you can research ESXi and see if that is something you would want to pursue. The benefit with that is if you are planning to run a NAS, then you can pool individual drives as a storage and make a RAID for something like freeNAS 8 w/ ZFS. Core i5 should be plenty but if you can do consider core i7.

I know some people feel standard windows in a server is sacrelig. But I am still looking for the advantages with all this complicated setup. Not my machine though and not trying to knock anyones setup. Just wondering if its worth it for someone new to all of it.

OP in your title you mention "htpc" as one of the requirements. You also say you want this to "be able to use it to feed my home theater room". Did you mean using this machine as an actual htpc as in hdmi to the home theater? Or feeding the home theater as in serving media to it?
Just thought that would clear things up a tiny bit. Good luck to you sir. I'm sure it will be fun whatever road you choose. I'd love to hear your results if you end up going the VM route.

I built a very similar box (minus some storage capactiy) and wanted to do the same thing.

I was interested in ESXI5, but like you I thought it seemed complicated - and I wasn't sure how video for the HTPC portion would be (would it be equivalent to running straight windows, or laggy and not as good?). Do if you decide to try the ESXI5 please let us know how it goes

Ok thats the first part I would consider. If win 7 is not the base you need to do HD video/ possible HD audio bitstreaming out of the vm software. While probably possible just another hurdle to consider.

Just ran across this, not sure how old it is.
Run freenas in a virtual enviroment

And it refers to using Virtualbox which is a free open source virtualization app.

What are you going to do to get the Mid Tower(I'm assuming) to blend into your room? Most HTPC guys want a small case or at least a horizontal case that looks the same format as your standard receiver.

Yeah, if looks isn't an issue I still prefer the tower layout.

The main concern with Windows 7 as your base instead of ESXi or another dedicated Hypervisor, is that of graceful recovery of VMs in the event that the host OS has to reboot, or suffers some sort of crash. ESXi pretty much never has to be rebooted unless you're changing hardware or applying one of the very infrequent updates that is released. Windows 7, on the other hand, would need to be rebooted quite a bit more often for updates (yes, you could turn them off, but that is risky on a system that is housing that much data). That means ensuring that it safely powers down all the VMs before doing so - without native OS support for it, that can be a tricky feat to accomplish in any sort of automated fashion. There is also the issue of passing hardware through to FreeNAS - I don't think you could do this in Windows 7, so you'd be forced to create virtual disks on those drives, and then have FreeNAS use those. While that would work, it does introduce another layer of complexity into the system.

Now, another option if you'd prefer to stick with the familiarity of Windows would be using Hyper-V as your base, though you'd have to learn how to manage it through remote tools or the CLI unless you have access to a full copy of Server 2008 (or 2012 when that releases next month), since the free version of Hyper-V does not have a native GUI.

You already knew this, just trying to ensure the best setup thus over complicating things. :P I do the same thing....

I've got a similar setup btw and it runs great. My main HTPC serves as our main tv, ripping, encoding, connecting to an external 4-bay (for now), and shared to my sons computer and daughters apple tv through SMB shares.