Right now the best tablet would be the Galaxy tab, but with Android 3.0 being released just around the corner, which is designed specifically for tablets I would wait for that.
This will be the mother of all tablets:
http://nexus404.com/Blog/2011/01/07/ces-2011-motorola-xoom-honeycomb-tablet-coming-to-the-uk-too-motorola-xoom-android-tablet-confirmed-for-the-uk-rest-of-world-also-waiting-anxiously/
Runner up:
http://www.engadget.com/2011/01/06/t-mobile-g-slate-revealed-at-ces-press-event/
The problem with any the Galaxy tablet is that it runs on Samsung's modified android, known as TouchWiz, which is the same as the Galaxy S phones. It's not pure android, so probably not the best way to make people familiar with android. Then Android 3.0 is completely different than 2.1-2.3.
Right now to get an android tablet that runs vanilla android (the way google makes it) is quite a task. They are mostly crappy chinese made devices that run on outdated versions of Android.