Right now, it's... hum... affrodable ? Geek gadget or rich gadget.

3-5 years, it will be cheaper, but still a high-tech gadget (like having a Blu-Ray burner the first year Blu-Ray Movies goes on sales).

4-6 years, they will be an usefull tool to have at home. Most home will have them. <- We will see many people complain about it too. Telling it will kill the industry, trying to put DRM in stuff and so on (like the MP3).

6-8 years, expecting they will go very cheap and be a "must" in most home (like having internet... you can live without it, but it's WAY better if you do have it).