If I want to sell it after say a year or so.... I cant because its permanently linked to my account?
You can't remove it at this point without Google intervening (which they may be able to if you call them). However, that's a one-time deal. The Google Help Text says it will send your username to it once. A factory reset should remove that, and is a good idea if you ever wanted to sell your device.
So if you're concerned about having it on there on first powerup as per your initial question, you'll have to call Google and see if they can cancel the signal that is waiting to hit your device and initialize your username onto it. They probably can, and it will start up the very first time with no knowledge of who its new lord and master is.
If you're concerned about removing it before a resale after using it for a year (or a day), do a factory reset and it should just go back to "Welcome, unknown user, please enter your email and password". You can test this by factory-resetting it as soon as you get it out of the box, and it should immediately forget your email address, because the signal should only be sent once.