Like Req said, if you only plan on watching basic channels you might not want to get a DVR since almost all DVRs have to have a subscription and it might be a waste of money. But if you do want DVR capabilities, you can get away using others ones that don't have subscriptions, albeit they are more expensive/rudimentary.
Here's the non-subscription way:
http://www.usatoday.com/tech/columni...-22-dvrs_N.htm