Sounds like power is a non-issue to you, so a MacBook Air would suit you well! Just decide between the 11" or the 13" and you will be happy. If your always in the go you cannot beat the 11", but if you tend to leave the computer at home go with the 13", depending on budget.
Yes, I agree with MacintoshDan. If you are only going to be doing basic tasks like web browsing, media viewing (movies, music, etc.) and email, the MacBook Air will perfectly suit your needs. Most of these tasks were nailed perfectly by computers several years ago so even the most basic models do them perfectly now.