Finally ordered the parts for build #2 (basic home office / lite-HTPC)! Went with the same mobo and RAM as build #1 [the Asrock H67M-ITX and 8 gigs of G.Skill Ripjaws], but put in a G620 instead of an i3 to offset the cost of the SSD I got for my OS drive. All these guts will go into my Rosewill case from build #1, and build #1's guts will go into an IN-WIN BP671 case that'll tuck nicely behind my bedroom TV.
Once build #2 is complete, I'll have a vintage ~2005 PC with no home. Here's where I'm hoping you can give me some opinions.

I am planning a H61/G530-based micro-ATX server/lite-HTPC build. I could put it into the case from my old/orphaned PC, and save the $ a case would cost... or I could buy a new case, and try to recoup some $ by selling the old PC.
The old PC is in a c.2005 Enlight mid-tower ATX case w/ ~400W power supply. It's got a Pentium 4 @ 3 GHz, MSI mobo, 2GB Corsair RAM, Radeon 9800 AGP video card, Sony DVD-RW drive, an 80 GB 7200 RPM Hitachi HDD. Any chance I can make $50 - $100 selling this old space heater, or should I just re-use the case?
If the motherboard had PCI Express instead of AGP, I'd almost consider popping a cheap video card in there and keeping it (even though it is a bit of a power hog).