YOU "BUILT" ONE? excuse me? :) are you talking about a DVR? probably not.
In today's NY Times
Does a DVR Boost Viewing Hours or Not?
http://www.nytimes.com/2006/07/31/technology/31drill.html?ref=media
an HTPC, and yes they function as a DVR and are quite easy too build. Here let me link you to an how to for you doubting thomas.
http://www.ramelectronics.net/html/HTPC.html
http://www.engadget.com/2006/01/24/how-to-build-a-practical-htpc/
http://www.firingsquad.com/guides/building_home_theater_pc/
This is just the first few links on Google. Maybe you can do a little investigation yourself before coming to some uneducated response again.