Use text messaging (Score 1)

Another possibility is to implement this using text messaging in addition to whichever phone you decide on, since text messaging works almost exactly the same on pretty much every phone out there. E.g. text "lights" to get the status of your lights, and text "lights off" to turn them off. You could also set it up so that you get text alerts to your phone when something you're monitoring in your house changes. The other good thing about text messaging is that you can validate based on phone number, rather than relying on the security of a password on a web browser (think house key vs. house keypad).

You can set up something like this for free literally in minutes using the phone number DOTCOM (368266), which lets you send and receive text messages to and from every internet domain name ad-free (just drop an index.cmrl file on your webserver). See:

http://dotgo.com/publishers

and

http://www.dotgo.com/support/documentation/doc0001.1.0/html-1/

(Disclaimer: I'm a co-founder of DOTGO)