Let the hive mind of Engadget get that for you.
"I need help! I want a small pocket camcorder but I'm not sure which one to get. I don't want to fall into the hype of the Flip because I worry two hours won't be enough. What should I be looking for when considering a small camcorder and where can I get a good quality one with expandable memory? Thanks!"
If you order HD service through your cable company and use Cablecards for access, you may need one of these tuner adapters to properly tune in some HD stations. They should know whether you need one or not. Not too many cable companies have gone SDV, but it looks like it really helps them cram more HD stations in, so expect it to be almost mandatory in the future.
Thankfully it seems the cable companies that DO require SDV tuners, are just tossing in the equipment at no additional rental cost. I think if they did, the FCC would come down on them since they're mandated to offer Cablecard access to all their stations and SDV "broke" that and this is their way of keeping out of hot water and being fined to death.