I think that the whole argument about smart phone vs. the tablet vs. the laptop is ridiculous. There is no overlap. Tablets will never replace the convenience of the phone, no matter how small they get, LOL. Also, they will never be able to compete with content creation abilities of a traditional laptop or desktop computer. Have you ever seen a hardware setup of a typical software developer or an artist? If anything we may see a convergence of a phone and a laptop with an optional display and input hardware, but tablets have only one way to go: simpler and cheaper.
Where tablets excel is in content consumption. IMHO, they will become a cheap commodity used to quickly check your email, search/browse the web, stay connected through social media or video conferencing, read the news, etc. or to keep your kids entertained on your way to grandma. You will not be using them to watch TV or play games at home - not if you have 60" display and next generation gaming systems in your living room. But you will most certainly use them to quickly check a recipe while cooking or view the latest photos or home videos of your grand kids.