I've been planning on building an HTPC and have been caught up on the hardware. However I've come to realize that the software is much more of an issue at this point.
Stream Amazon video on demand
Watch cable TV
possibly other light controller friendly games
OS can be Windows or Linux.
Right now streaming both Netflix and amazon is the issue. I've read that an amazon plugin is available for windows media center but am unable to locate it. I tried the Netflix plugin for windows media center and it doesn't even let me log in. Most other software doesn't support Netflix and none of them even mention Amazon.
The problem with Amazon unbox is that I want to stream the video's from the internet, not download them to a computer and stream them to the htpc. My goal is to be able to sit on my couch, select a video I have purchased, and immediately begin watching it, without having previously downloaded it.
I guess I just want the htpc to be a stand alone media center, not just an extender. I'm also trying to limit hard drive usage so I can use a small ssd to eliminate heat and noise from a large disk drive.
I would recommend media center as well. But I don't think Amazon supports streaming for WMC. You may look for a plug in for it.
You will also need a cable TV tuner in your computer to watch cable TV. If you are going to recode any TV shows you might want a bigger storage drive. I record them in HD and there between 5-7GB for a hour long TV show.
I have also played around with XMBC http://xbmc.org/
I might have an Amazon plug in.