AppleInsider quotes ThinkEquity analyst Jonathan Hoopes:
Apple TV can, in our opinion, be easily turned into a DVR with little or no hardware modification and a software upgrade
If we define a DVR as a device that time shifts broadcast content (I do), the current Apple TV will never be a digital video recorder. A DVR needs to get video from somewhere… As far as I can tell, Apple has not hidden a tuner or any video inputs in the box. I suppose it is possible they could team with AT&T (Xbox 360, anyone?) and make this into an IPTV platform (with DVR capabilities) of some sort, but I’ll believe it when I see it.