Answer phones kind of suck in much the same way that 1980's era Walkmans (Walkmen?) suck compared to MP3 players.
You've got to wonder how hard it would be to have something the size of a cigarette packet containing a Gumstix and some sort of solid state memory card running Linux and Asterisk that replicated the same sort of voice mail functionality you have on your mobile phone but for home. No tapes, no rewinding and the ability to archive messages.
Then from there, sell a more advanced version - multiple inboxes for different members of the family or remote access or something.
Finally the super-combo mega-deluxe royale with cheese version with Ethernet. It could do transcription of the message and email or SMS it to you. Or just email you with the MP3. Or allow you to access your messages via the web and play the messages back using an embedded Flash player. It could redirect calls or route people to Skype. You could set it up so that only certain incoming numbers or those with a PIN code could phone you during certain times.
I'm not sure if thinking about stuff like this means I should get out more or less.