What should I do with these leftover PC components?

Inspired by this thread. I recently upgraded my system from an AMD AM2 dual-core, to an AM3 quad core, and am left with more additions to the ever-growing list of surplus parts I have.

So I got to thinking - what the heck should I use these parts for?

For context:
I have two PCs (my main PC with Win7, and a PC currently with XP that I’m planning to use for a “scratch” system to play around with Linux and other stuff), my wife has one, my kids have one, and I have a Windows Home Server. So I’m not lacking for systems.

I have the following parts:
[li]Gigabyte 690G micro-ATX motherboard; pretty vanilla - HDMI, 1 10/100/1000 port, 4 SATA ports[/li][li]AM2 Athlon x2 5600 with stock heatsink[/li][li]2 GB DDR2 800 Kingston ValueRAM - barebones basic stuff, not for overclocking[/li][li]1 old Socket 939 single-core AMD system, with an Athlon64 3700+ processor, full ATX SLI mobo (PCIx 1.0, though), 2 GB DDR 400 RAM, no video card - all this stuff is so old it needs to be treated as a single unit, since I can’t upgrade the CPU or RAM[/li][li]2x160GB SATA1 hard drives[/li][li]large-ish Apevia X-cruiser ATX mid-tower (no PSU)[/li][li]1 slim HTPC micro-ATX case with a 300W PSU (PSU isn’t ATX standard, so it won’t fit in a normal case)[/li][li]2 optical drives - 1 SATA DVD ROM, 1 IDE DVD R/W[/li][li]1 stick DDR2 667 SO-DIMM laptop RAM (can’t remember how I wound up with it, as I’ve never owned a laptop outside my work-supplied system)[/li][li]And assorted keyboard, mice, brackets, cables, adapters, screws, etc.[/li][/ul]
Most of these parts are still very capable, but I honestly don’t know what to do with them - normally I give my old hardware away, but it seems such a shame to not use some of this stuff, especially the newish mobo/CPU/RAM combo. And I’m a gadget hound.

So I ask - what would you build with it?

HTPC, duh.

Make a torrent box, if you’re into that kind of thing. Or a raid NAS box for storage ( with some more disks. )

That would be the obvious choice, right? I forgot to mention that I had one and I didn’t like it (that’s where all this stuff was originally installed a couple years ago, before I dismantled it and reappropriated it for my personal system).

I had the whole setup, running Vista Media Center, connected to my home theater system, controlled by my (now dead) Harmony remote, all prettied up and everything. But the Media Center software was lacking, and the 690G chipset isn’t really that great for decoding video content - even high-bitrate 480P videos would stutter, and Netflix was a slideshow. Between Netflix on my PS3, and XBMC on my Apple TV, I pretty much have all the functionality of an HTPC without using up the shelf space in my living room.

I don’t need a NAS box because the version of Home Server I’m running (pre-Vail) lets you set up an ad-hoc RAID-lite sort of setup: you can add drives (internal or external) and designate them as data drives or backup drives, and for specific shares, you can stipulate that the data should be mirrored on a different physical drive. It’s kind of like a RAID array, but without the headaches or floppies. Stupidly, MSFT took that feature out of their new Home Server version.

But a torrent box isnt’ a bad idea. Right now my home server is running on a single-core Atom box, so I’ve been avoiding running any extra services on it, but I could build a box to pull torrents, and point them to the Home Server for storage. I’ve never tried to automate torrents before, so it might take some doing, but I’m game for that. And it might help me in my goal of becoming cable-tv free (if I were into that kind of thing ;)).

Vuze + ScaneRSS + a reliable subscription-based torrent site = awesomesauce

Sweet - thanks for the suggestion!