We've been using these Kidde dual sensor smoke alarms: Kidde PI2010 Very few false alarms.

We use these CO detectors in most of the house: Kidde KN-COP-IC tied in with the smoke detectors.
We installed this one in the hall by the bedrooms: Kidde KN-COPF-i
The blue numbers are bright enough to act as a night light.

We're happy with them all.

You're welcome.

Thank you very much Robj for taking the time to let me know about Kidde brand. I'm a little overwhelmed by all the different types out there. Is there a reason why you chose 3 different types to install in your house? Are there ones better for certain areas? Thank you.

Actually there are two different types of CO detectors there. The first is a smoke detector.

We had the Kidde KN-COP-IC CO detectors on each level of the house and when it came time to replace them (they're good for 7 years) we tried one of the new Kidde KN-COPF-i detectors as, being recessed, it hides better. We liked it so much we installed a second but used the cheaper one in the basement.

We do have a third type. Its the Kidde KN-COSM-IB combo smoke/CO detector that speaks the type of alarm: it says fire or carbon monoxide so you know more quickly what potential emergency you are responding to. As everything is hooked into one circuit, they all communicate with each other.