I have been getting more and more motivated to build my own PVR lately despite the fact that I already own two Series 2 Tivos. I guess a big motivating factor is that I want something that can do HDTV instead of just standard definition television.
I personally do not have a High Definition television but I have had a chance to see plenty of shows in high def from my computer and I am impressed! Anyway, here are two new resources that can be valuable additions to the normal places for information (like http://mythtv.org and various discussion boards).
The first is a 15 minute video from former TechTV host Kevin Rose on his new site called Systm. Their second episode is somewhat of a HOWTO for building your own MythBox.
The second resource is an O'Reilly article called "Building My MythTV Box, Part 1: Hardware" that has very sound advice and does a great job of making some of the tough decisions on what to use for your HTPC.