Roku

We've had one for about 6 months now. We have it and an antenna so we have inexpensive access to lots of digital TV.

Good:
Lots of channels
Wifi or Ethernet connectivity
HDMI and composite outputs
Dependable
Relatively cheap
Low power usage
Easy access to Netflix, Amazon, pay-per-view, Pandora, etc
Can play own media via USB port (from a hard drive if you lke)
Can use as a media server to play media stored on a network computer or storage device

Bad:
Even though there are lots of channels you may find them wanting if you like sports (I don't)
On-screen user interface could use an update
No closed captioning (I think)

Hope that's helpful.

Edit: oh yeah, we're on DSL and when we're playing a movie all other network traffic really slows down. Netflix uses all the bandwidth it can to ensure picture quality. So me surfing on the my laptop while the wife watches a chick flick is frustrating.

I bought one for my Netflix account and like it overall. I've had it about a year now. Although, I don't watch it all the time, it is nice to have. My only gripe with Netflix and not Roku is that they need to offer more movies. Their choice is still limited. I don't subscribe to any of the other Roku supported channels. I don't regret buying mine at all. It works well and has several different ways of connecting to your devices. I hard wired mine instead of using the wireless function. Unfortunately, I have an older Roku box that does not support High Def. I think all the new ones do now. I don't have a High Def TV yet (and probably won't for a while), so I'm not really concerned about it.

As said by Semipro, Closed Captioning is not available yet. That's probably my biggest gripe. Hopefully that will change later.