Well, for the things you listed, both would do quite well. The Imagio and Windows Mobile do still have the advantage for game selection since Android games still tend to be simple 2D style games. The Imagio's on screen keyboard is decent and the Droid's hardware keyboard isn't one of the best, so that's a draw unless you're accustomed to hardware keyboards. Some folks just can't give up a hardware keyboard if that's what they're accustomed to. Both have very good YouTube players.
-------------------- Lisa Gade Editor in Chief, MobileTechReview