I know lots of people surf these forums for advice and I know I sure did! So here's my contribution to my Karma. After spending a good long time struggling over decisions and configuring stuff I came up with a build that I'm very happy with. If my goals are like yours, and you're as anal about the details as me, then hopefully this post will help you decide.
1. Quiet - not silent, but not obtrusive for low volume music listening
2. Under $600 pre-OS
3. Classy stereo-like appearance
4. Durable high quality components
5. Ability to easily handle any HTPC task, up to 1080p with surround sound over HDMI. No Blu-Ray will be installed initially, but I want full Blu-Ray support. When burners are cheap, I'll swap my DVDRW for a BluRay burner.
6. No need for games
7. Generally easy setup
So with those goals in mind in January 2009, I chose:
Antec fusion Black v2 with the stock 430w Earthwatts PS
Gigabyte GA-MA78GM-S2HP with an Athlon 4850e and 2x2gb of 1.8v name brand lifetime warranty RAM
500gb Seagate 7200.11 recycled from my recently deceased MediaGate media player (though you can buy a 2 platter 640gb WD and keep it all under $600 as of Jan 2009)
Scythe Ninja Mini
1 x OKGear brand Yate Loon manufactured 120mm Case fan model D12SL-12
BTC 9019URF wireless keyboard with integrated joystick
Samsung DVDRW drive
How to build for optimum noise levels:
SPCR said the Fusion would be serviceable in stock form and I beg to differ. I think anyone who cares about noise levels would find it outrageously loud, and don't SPCR people care about that? Anyway, I tried it stock and it was totally ridiculous, whirring and whooshing away on top of my top of my AV cabinet like a helicopter on a landing pad.
Why on top of my AV cabinet? Because the Antec case is 17.5 inches wide, not 17 like my Onkyo receiver, Sony SACD player, Belkin line conditioner/surge protector, and every other piece of AV equipment in the world. You can tell Antec makes PC gear, not AV gear. Anyway, it still works out for me but be aware of that little niggle.
As for the noise, here's what I'd do if I were doing this again in order to skip my bumbling around.
First, pop open the Earthwatts 430 unit and remove the 80mm Addo helicopter simulator. It's just plugged into a simple two pin fan header, so this as easy as pie. Just unplug the Addo, pop in the 80mm fan that comes with the Scythe Ninja mini, twisty tie the excess cable to keep it neat, and plug the three pin fan cable into the two pin internal PS fan header such that the red and black wires are clearly the ones getting connected and the yellow cable from the fan is left unconnected to any pins. No 2-pin to 3-pin adapter is required, at least not on the Earthwatts 430. That yellow cable is just rpm monitoring and since the PS doesn't support that anyway, you won't miss it. I believe that this power supply just sends volts to its 80mm fan according to its loading level. If you load the PS more, it'll automatically send more volts to the fan, figuring it needs more air flow. In any case, I can tell you from experience that I have had no problems at all with the Addo/Scythe swap.
The new fan is QUIET and its at least spinning and removing some air. I have no stability issues. The difference is TREMENDOUS. The Scythe fan is barely, barely audible even to my critical ear. You do void the warranty doing this swap. Grow a pair. A nice, quiet replacement power supply is $55. Besides, with this build, the power supply won't be stressed one bit even if you run it at full load constantly.
OK, now that you have turned the noisiest moving part in the computer into the quietest moving part, put everything in the system except the stock exhaust fans. I plugged both a stock Antec TriSpeed fan and the Yate Loon into four pin molex connectors to compare their noise levels at full blast. The Yate Loon on full was just a tiny tick louder than the Antec on quiet and at lower speeds, the Yate Loon is much quieter than the Antec on low. Install a single Yate Loon or other very quiet 120mm fan in the exhaust vent towards the front of the case. That's the leftmost vent as you look at the side. I installed the vent blocker plate that came with the case over the other hole. Then I installed the included expandable air baffle on the inside rear panel of the Antec case. That little piece routes air coming in from the vents on the back of the case (via negative pressure created by the exhaust fan) over the top of the motherboard and through the passive CPU cooling fins. I plugged the exhaust fan into the CPU fan header since the fan is only about 15mm from the heat sink. This way, if the CPU gets hot, the exhaust fan will spin up and suck more air through the Ninja Mini. That's it for cooling. It sounds elegant, but how does it work?
Using my Kill-a-watt meter, I tested my config's power draw. In hibernate, it takes about 3 watts. On the desktop doing nothing, it draws about 50. At full load, running a ton of CPU intensive programs and disk defrag and listening to a cd, I got it up to 100 watts. On boot, I saw it hit 125 watts for a second. That's barely enough to get the power supply into its 80% efficiency range so power draw is quite acceptable to me.
Noise-wise, then system makes a gentle windy whoosh. I have it positioned about eight feet away off to my right and at a 90 degree angle to so the exhaust is blowing towards me. It's noticeable, but not as annoying as the stupid Scientific Atlanta 8300HD whiney piece of crap cable box underneath it.
I ran a file sharing program all night and I got the northbridge (the hottest temp sensor) to 32 degrees C so under low load there's no issues. I have the exhaust fan controlled by the Gigabyte BIOS because no matter what I change in the BIOS, I can't get speedfan to do anything to the fan speeds. After an hour of playing two seperate DVD rips and writing this post and running the file sharing program and playing mp3's with full screen visualizations turned on and Kaspersky Internet security sunning on the background of a Vista x64 Ultimate installation, the highest temp speedfan has reported was again the northbridge, which got up to 35 C. The other temp sensors were 31 and 32 C. That's basically not even warmed up. My ambient temp is about 64 F/18 C, so that is pretty chilly, but I can't see how 35 C under load could tun into anything to worry about with moderately higher ambient temps.
Under the load I described above, the CPU use chart jumped up and down between 15 and 50 percent. That's a good load scenario for my use - it's more than I'm likely to do, but I'm not doing some silly 100% stress test that I'll never ever simulate with real usage.
While playing a 720p movie trailer encoded with h.264, the Athlon 4850e was at about 15 to 35 percent utilization. I tested with AV, speedfan, and a p2p program running and no reboot or anything. A 1080p H.264 file stressed the system at about 35 to 55 percent. So basically, if you can run file sharing and AV and a utility and play 1080p files perfectly smoothly, then this system does all an HTPC needs to do.
As prices drop, I'd love to swap the 500gb hard drive for a low priced SSD and then run a USB cord to an HD enclosure buried in a drawer or otherwise wrapped up to be quiet.
I'd like to figure out how to make speedfan control the 120mm fan so I could further slow it down. The BIOS control keeps it at about 1000 rpm but I bet I could run it slower.
Eventually I'd like a burner that can do blu ray and DVD's - they'll probably be cheap before too long.
Last, I'd like to get my Onkyo TX-SR605 to work with the Gigabyte motherbaord so I could get audio over HD instead of running a aseperate optical cable. I have no idea how to do this outside of ridiculously obtuse custom monitor drivers that I can't begin to comprehend.
I love my system. The LCD on the Antec Fusion Black is worthless and the case is slightly too wide but I can personally easily live with those drawbacks. The system still whooshes a bit but overall it's acceptable. Its not great - great would be not hearing it at all - but its pretty good. The sound it makes is low frequency and not as annoying as the cable box, which has a high pitched whir that's not as loud but is more annoying. I bought everything except the case from newegg. The case was a lot cheaper from Amazon.
Thanks to everyone on this forum for lots of help!