What is the best router/modem to connect Apple devices to Comcast

If you havethe latest Xfinity cable box available, it has Wi-Fi built in but you can connect an AirPort Extreme for fasters speeds and better security > http://www.apple.com/airport-extreme/

That gives you two Wi-Fi networks. If for some reason your AirPort needs restarting and you need to go to the web for help, you can use the Xfinity Wi-Fi network as a backup.

Works great for me.

Ask Comcast what modem you should get. An AirPort Extreme will work fine as a router, but it is not a cable modem.