I'm trying to figure out how to build a cheap, silent, general purpose system. By cheap, I want to keep it to under $400 without software. By general purpose, I mean web browsing, video playing, occasional transcoding and music playing. Main media storage will be on a NAS.

It seems to me that when building a silent system, the costs ratchet up quickly because all the components need to generate a bit of profit for their manufacturers. I've been waiting for an integrated or barebone system that might allow some economies of scale.

I just noticed the new Shuttle XH61 barebone. It comes with its own power converter, external adapter, CPU cooler, fans and motherboard in a solid case for under $200.

For a budget build, I was thinking of the following system:

Shuttle XH61 - $180
4GB value RAM - $22
Intel G530 CPU - $60 (a capable CPU, on par with a Core2 Duo E8500 prom a couple of years back)
Crucial M4 64GB SSD - $95

Total = $357 without optical or OS

Again, the XH61 appears to come with its own CPU heatsink and fan, and its own case fan. I read one comment somewhere (http://secure1.ncix.com/products/produc ... ?id=159621) where someone said they found them to be inaudible! Does anyone know if Shuttle has stepped up here - using cooling/fans that SPCR would approve of? If so, might this be the answer to my elusive search for a cheap, silent, competent rig?

A let reply in case someone finds this threads by putting keywords in a search box...

The XH61 includes a heatsink/fan but no case fan. The reason it's included is not so much to let you build a quiet PC cheaply but to allow you to cool reasonably powerful CPU even though there's not enough clearance for most heatsinks or much room for the heatsink to breathe. The point of this barebone is its dimensions, not silence.
Unless I got a dud, the stock XH61 is fairly noisy (as you might have expected from Shuttle). If you use a slow CPU and/or don't put continuous load on it, the fan won't have to spin fast. At the lowest speed, the noise of the stock fan wouldn't bother most people. It's not SPCR-quiet however and it isn't hard to do better cheaply even without a case fan or a third-party heatsink, for instance with an open Antec or Morex case and Intel's stock cooler at ~1500 rpm.
The cooling and the noise are better without the standard drive bays in case someone wants to use this case without a hard drive or an optical drive. But if you want quiet, you aren't going to avoid a fan swap (or more serious modding) anyway.

Thank you.

So what would you suggest for a budget, 'inaudible from 3 feet' build? Specifics please. Can I get inaudible for under $400?

Thanks.

Your query is hardly specific. What's inaudible? What do you want (CPU, size and so forth)?
Even with the stock Shuttle which is far from inaudible in my opinion, lots of people would reply "what noise?" if you asked them is they mind the noise while the CPU is idling. Background noise is also important.

If you want something like the XH61 but quiet enough in most cases, in theory a nice open case which takes a Kozuti should do fine for a G530. There are cases which come with a fanless PSU and which allow you to mount drives under the board where they don't impede airflow. I mentionned the most proeminent vendors above. Add the Kozuti and a cheap board and it'll cost more or less what the Shuttle costs (depending on parts availability in your locale, shipping costs, etc.). But these cases would be thicker than the Shuttle and wouldn't look as sleek.
Obviously if you're OK with a larger case you could get less noise without breaking the budget.

In my experience with former shuttle modells the emitted noise mainly came from the power supply with a smallish turbo fan.

Cheap and silent w/o optical drive could be based upon ISK 100 Antec.

http://www.silentpcreview.com/antec-isk100

Smaller and quieter as anything that ever came from shuttle, imho.

I don't think it's smaller than the XH61 actually. And it lacks features compared to the Shuttle. But noise-wise it should indeed be better.
If you want an optical drive and slightly better cooling, try a Morex T3500.

The ISK100 lets the HDD get too hot. My #1 cooling concern is the drives, because it's the thing I've had the most problem with in the past in a couple of fanless systems. This time, I'd like to build a single fan system, inaudible from 3 feet, that keeps my hard drive cool. Any suggestions for case and cooling?

Seems like you should deploy a solid backup strategie. In wanting a small case, you will always make compromises.

You want cool harddisks? You should either think about a case, that cools your disks well and see where you end up size wise or you should just take it for a fact, that your (any) disks will fail sometime somehow, mostly when you do not need nor expect it.