Finally got around to building Qian a PC of her own. Cobbled together pieces of my old P4 box (case, power supply), my newer desktop (my older monitor, 2GB of RAM [of which 1GB was inaccessible to 32-bit XP anyways]), and some peripherals she had for her laptop (keyboard / mouse), et voila, a $250 desktop (including tax!). And it runs pretty fast to boot, almost can’t tell the difference w/ my desktop.
There were some new parts (little reviews for each):

• Intel Pentium E2180 Allendale chip (2.0 ghz)
  This is the new replacement for the Celeron. It’s based on the same microarchitecture as the C2D, just with less L2 Cache. Definitely fast enough for non-gaming use.
• Intel DG35EC mATX G35 chipset mobo
  Main thing here was that it has everything I needed, including a DVI and HDMI output. This is a pretty complete board featuring the X3100 integrated GPU, ICH8 (which for some reason doesn’t have XP 32-bit AHCI drivers?) and built in gigabit/sound. A little on the spendier side for motherboards these days ($100 off of newegg), and definitely not a OC’ers board, but that’s exactly what I wanted. It comes back from standby very quickly (I’d say a second or so, feels like a Mac)
• Seagate 7200.10 250GB hard drive (3.0GBps SATA)
  This is pretty standard, though I see that they make them slimmer than they used to. Probably one has one platter.

The mATX case went into a recycled Lian Li Aluminum full ATX tower case. Which leaves for a very empty inside, especially with no extra PCI cards. This lets me keep the noise down by not plugging in any of the case fans. CPU seems to stay plenty cool with just CPU and power supply fan.
I was interested to see how power-hungry this minimal box would be. The other relevant part power-wise is the 430W Thermaltake power supply. It’s not particularly quiet (two fans) nor efficient (not 80-plus). With all of it plugged in, my kill-a-watt tells me that the wattage from the socket is 70W at idle. That’s higher than I would have liked, but it’s fine for mostly-on-standby machine. My desktop with a Seasonic efficient power supply and C2D E6600 measured in at 110W idle, also higher than I expected.
I did the math to see how much this actually costs me. One watt of consumption left on 24/7 for a year comes out to about $1 on the electricity bill, at the SF standard 12 cents per KWh.
I’m still doing research to build on always-on home server. It looks like trying to get under 50W (ideally 40W) at idle will be the goal there. I know it can easily be done with a VIA board, but I’m not so sure of their Linux support.
I risk of starting to sound a little old, but it’s amazing to think that you can almost buy a full pc for $300-400 these days. In 1992 dollars, that’s about $200 (1992 is when I first started really caring about spending my own money to augment our home PC), and $200 maybe got you a new hard drive back then.
On a final note, I’m back down to one monitor again. Feels kind of cramped, and at the same time refreshingly simple. Dual monitors is nice, but always adds extra stress when managing windows. Maybe this will motivate me to resume my search for a new monitor.