High End HTPC

For starters, I highly recommend you read through this guide and the FAQ right after it:

Assassin's Simple/Beginner HTPC Buying and Building Guide

Now, a few comments from myself.

An SSD is a luxury for an HTPC. They are nice to have (my HTPC has an SSD), but a properly set up HTPC does not boot very often. Instead, you need to use S3 mode and even platter HDD's are ready to go after 2 seconds when using S3.

The i5-2500 is way overkill just for HTPC. You may want to consider scaling back to an i3-2100 (which is still overkill).

With the Sandy Bridge CPU's, you have built in video that is near perfect for HTPC use. You would have to change your motherboard to an H67 chipset to use the video, however. If you plan to do any gaming, then a video card is warranted.

TV Tuner: I strongly recommend you get a dual ATSC/QAM tuner. The best options are the HVR-2250, HDHomerun Dual, and the A188 duet.

PSU: You want a quiet one. I recommend you look at Seasonic models, or one of the Antec Earthwatts units. Corsair is good too, and so is Enermax.

That should be enough to get you started. Post back if you have any more questions.

OOOOH I AM SO GLAD I CAN HELP WITH THIS!!!

I just built an HTPC and a file server last month.

For my HTPC, I used:

Intel DH67CF Mini-ITX
Intel i3-2100
2x4GB Corsair c9 DDR3
OCZ Vertex 2 60GB SSD
Silverstone SG05B Case w/PSU included (not the 450W version --- OVERKILL)
Stock CPU Heatsink/Fan
Windows 7 Home 64-bit

Total cost including OS: $600

This thing is DEAD SILENT. The stock heatsink/fan is AWESOME! My temps are around 30-32C streaming 1080p Blu-Ray ISOs with HD audio output via HDMI to a Denon receiver. According to CPU Temp, the highest temp I have hit is 40C. I have not played with Prime95. There's no point. This CPU will never fully be pushed. The stock cooler is silent and keeps things cool enough for task.

Your needs may be different than mine. I will try to upload some pics of my HTPC and file server tomorrow evening to this post so come back later. I wanted a case that fit in my current entertainment center. I wanted a build that was SILENT. The case I chose will sport a thin Blu-ray drive, which I did not need/install. I rip my movie collection to Blu-Ray ISO from my gaming machine, then copy it over to the file server.

This is what I have found. According to Core Temp (gadget), when I am streaming a Blu-Ray ISO from the network with Arcsoft TotalMedia Theatre 5 (within Windows Media Center auto-mounting ISO with VCD), I am using about 10% of each CPU core and about 20% RAM. That's 1080p with TrueHD or DTS-HD Master audio!!!

Obviously the i3-2100 is overkill. Obviously 8GB RAM is overkill. I could have saved money on the RAM but it doesn't really make sense to save money on the processor. The motherboard was a tad expensive at ($120) but I grabbed the CPU for $100. You really aren't going to save that much by going with a lesser combo. Here's the great thing about the combo.

Did you notice I did not list a discrete graphics card? I'm running the Intel Graphics 2000 with the H67 chipset. It's great. I wouldn't try to play any hardcore games with it, but it's more than adequate for an HTPC. Why use the H67 integrated graphics instead of a discrete card?

NO EXTRA HEAT! NO EXTRA POWER! NO NOISE!

People on the net have tested the wattage of the i3-2100 systems and have reported ridiculous efficiency. I don't remember the number, but it's nowhere near the TDP number of the CPU. I agree with the other poster that SSD is novelty for an HTPC, but at $100 (after rebate) for a 60GB, why not spend the extra dough. I don't know what you'd spend on a cheapo HDD, but the SSD isn't that much more... $30? The benefits are NO NOISE, NO VIBRATION, NO DISCERNABLE HEAT, NO SPIN-UP TIME (worthless for HTPC), INSTANTANEOUS WAKE, VERY SMALL FORM FACTOR. That's worth the upgrade cost, IMO.

For my file server, I am running

Asus P7H55-M Pro Micro ATX
Intel i3-550
2x4GB Corsair c9 DDR3
OCZ Agility 2 60GB SSD
Antec 1200 v3 Full Tower (12 HARD DRIVE BAYS!!!)
Stock CPU Heatsink/Fan
Lots of Samsung F4 2TB drives
Syba SY-PCI40010 4-port RAID Sata II controller
Corsair HX650 PSU
Windows 7 Home 64-bit

Note the motherboard I chose only has five Sata II/III slots. That's why I added the Syba controller. I'm not using it for RAID, just the ability to connect more drives. I may consider doing it right in future and just using a 4u chassis and going with SAS, but I knew nothing about it when I built this last month. I still don't really know much about SAS.

The Samsung drives are VERY COOL and I have no fans running in the case except the CPU fan, which again is SILENT! I have shared two different 40GB files to two different HTPCs simultaneously with no issue. I'm sure I could do more on my gigabit network but I don't have reason nor hardware to test further.

Same with the HTPC, the RAM is WAYYYY OVERKILL! I should have gone with 2x2GB on both machines. I could pull a stick from each machine but then I'd lose dual channel memory. I'm not sure what affect that would have. I've already bought the RAM so I will leave it be.

I RECOMMEND THE H67 CHIPSET SO YOU DO NOT NEED A GRAPHICS CARD!!!!

(edited to add that I have not yet installed a product key for Win7 on the file server. I am off next week and one of the projects will be to install ubuntu on it and #^@% Microsoft for that PC.)

Yeah. I didn't know the Seasonic name at the time and I wanted modular cables. I wanted a clean case, and I couldn't get that with a non-modular setup. The Corsair only came with 2 power cables with 3 SATA power connectors on them for six drives. I sent them an email and they sent me two more SATA power cables for free. Planning on having 12-14 drives in this thing, I wanted things to be neat. I didn't want to have to use 4-pin molex to SATA adapters and all that nonsense, not to mention buying the adapters would add additional costs to another PSU brand.

Another reason I went with the 650HX was because Newegg had a combo discount for the PSU and the RAM, saving $30. There was also a $20 MIR. All-in-all, it wasn't a bad deal.

SSD's are like crack. Once your hooked it's really hard to give up.

I transplanted the SSD from my main HTPC to a new HTPC that needed a little speed boost. I went back to using a 7200rpm HDD WD black on the main HTPC and it seems soooooo sloooooow now launching WMC and loading media browser cache. The occasional reboot makes me cringe.

I know it's all relative, but I do miss the SSD. I need to figure out a way to sneak a new SSD in there without my wife finding out.

Thanks for all the advice guys, I really appreciate all the opinions. It looks like I can save a lot money too. I'll probably skip the GPU for now and go with integrated graphics, the Intel DH67CF Mini-ITX looks good, though I'd like the ability to a GPU later if needed.

I'd also really like to use a modular PSU to keep things neat, but that Corsair HX650 looks to be a bit overkill. Anyone have a suggestion for a reliable, modular PSU, probably about 500w?

And I'm still very much attached to the idea of using a SSD for the OS

There is quite a gap in the PSU market for good quality, quiet, efficient, low wattage modular PSU's. It seems most are ≥600W. Enermax had a line of modular PSU's called "Liberty" that were very excellent (my HTPC has the 500W liberty). They had a 400W model too. If you can find one of them online that would be a good choice.

looking for modular - zooted..

I have selective memory myself....

it's a good psu and it's modular, if you got the money then it's a good choice.
there are less expensive options but all in all the antec choice you found is good..