I gather people can ring you on your Skype from an ordinary phone - this correct? Definitely the case with Blueface (an internet phone co on which you can keep your old eircom number if you had one).
Also, I believe theres a device which means that you dont need your computer on all the time to make or receive calls or to know when someone is calling you. Fairly sure this is the case for Blueface, but not certain re Skype.
Come to think of it why would you need Blueface at all, wouldnt Skype do everything?, provided:
1. You've never had an eircom number, or if you did you dont mind losing it.
2. People can ring you via Skype from their ordinary phone.
The only other concern I'd have is the quality/reliability of internet phones. I think that, even if I manage to get broadband, it'll be a bit patchy so the question is whether its going to be so patchy as to make having an internet "home phone" unviable/unreliable/consistently annoying.