Your case is important because it is going to be sitting in your living room alongside your television, DVD player, stereo and so on. You don’t want some beige office PC cluttering up your home theater. Here you can either splurge on a custom, HTPC case or you can paint and customize your own. I went with contact paper and acrylic paint as a cheap solution to decorating a beige case.
Incredibly, your video card is a place you can save some money on your homemade Tivo. Unless you plan on playing some serious high-end computer games, all you need is an appropriate video out (s-video, DVI, or HDMI depending on your needs).
Make sure you don’t go cheap here. Go with a Hauppauge brand tuner card. At least the PVR-150. These are quality cards that take a load off your main processor.
You can get a card with 5.1 surround sound for about $50 (maybe cheaper on eBay). If you want to hook up with your existing stereo system, you’ll want to spend a little more on a card with an S/PDIF out.
To be safe, you should probably get 1GB of memory for your HTPC. Unless you want to play high end games, 1GB will be great and provide plenty of room for your programs.
Hard drive space is getting cheaper by the second, so you can choose to save or spend here. I have 300gb and it’s plenty for music and some TV shows. If you want to store all your DVDs, then start looking for some more space.