Wow, there are some odd ideas floating in this thread regarding HTPCs.
Personal experience highlights, take them with a grain of salt.
1. A good solid MicroATX motherboard is usually the primary key for an HTPC. The onboard DVI/HDMI outputs, as well as either coax or SPDIF digital audio out make them extremely ideal platforms for HTPC's. As you mentioned, HD streams don't see much acceleration from video cards. (See a note below.)
2. Dual Core is a
requirement for stutter-free playback/recording of multiple streams on an HTPC, and even more so on an HD HTPC. I started out with a single core AMD, and spent the money to upgrade to a dual core less than 2 weeks after the build was complete. It's not so much about the raw horsepower, as the ability to multitask effectively.
3. RAM is your friend. the more the better. I would say get as much as your budget or your motherboard can take, whichever comes first. ;) This may affect or be affected by your OS choice, so keep that in mind.
4. A Network connection (gigabit PCIe) is a preferred if not required feature for two reasons. First, the "Guide" in whatever HTPC software you use requires updates via the internet to accurately record your shows. Second, cramming a large amount of local storage in a small HTPC case isn't always the best solution. Sometimes it's better to have remote storage on a server or NAS, and simply pipe it over the LAN to your HTPC. This allows for easier and faster expansion of your storage options if you find yourself archiving hour after hour of HD content.
5. Most good Capture Cards/remotes have the capability to control an external Cable/SAT box to change the channel for your recordings, even if you are not around. The Basic MCE remote has IR blaster functions for exactly this purpose.
*Note: The current crop of video cards, namely nVidia 8500, 8600, 8800GT, ATI HD3850, HD3870 all come with hardware acceleration of the new HD formats, making them a possible upgrade choice if you find the onboard isn't driving your display the way you would like it. These few cards
do make a difference in HD playback, but not in the encoding process, which is up to the capture card and the CPU.
Here are some HTPC builds that I have had at least some experience with. They may be too pricey for you, they may be too cheap for you. But I can tell you they will offer solid performance, accoustics, thermals, and asthetics for an HTPC. :)
Code:
AMD System:
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85 AMD 65w 4400+ 2.3GHz Brisbane CPU
80 Gigabyte GA-MA69GM-S2H motherboard HDMI Output (ATI)
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90 nMedia HTPC 200BA Case
70 Antech NeoHE 430w modular PSU
100 4GB G.Skill 2x2GB kit DDR2 800 RAM
120 500GB Seagate 7200.10 SATA hdd
36 Samsung 20x DVDRW Burnner w/ Lightscribe SATA
110 Avermedia PCIe MCE bundle (comes with Remote)
105 Windows Vista Home Premium x64 OEM DVD
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796 Total before shipping
Intel System:
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125 Intel 65w E4500 2.2GHz Allendale CPU
77 Gigabyte GA-73PVM-S2H motherboard HDMI output (nVidia)
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90 nMedia HTPC 200BA Case
70 Antech NeoHE 430w modular PSU
100 4GB G.Skill 2x2GB kit DDR2 800 RAM
120 500GB Seagate 7200.10 SATA hdd
36 Samsung 20x DVDRW Burnner w/ Lightscribe SATA
110 Avermedia PCIe MCE bundle (comes with Remote)
105 Windows Vista Home Premium x64 OEM DVD
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833 Total before shipping
*Edit: One final note. As the price comes down on them, SSD's become a better and better choice for an OS (only) drive for HTPC's. This is due to their low thermals, zero dB accoustics, and fast ability to swap information to the page file. HTPC's aren't just "PC's in the living room" They need to do their job without drawing attention to themselves, much like the rest of the consumer electronics they share space with. With that being said, I usually replace the fans and CPU HSF units with aftermarket items I know to produce low noise and perform well. (Panaflo 80mm's, Vantec Stealth 92mm's, 60mm's, Zalman HSF's, etc.)
