My rough experiments (holding my 4G up to my face) show that an all-screen iPod like this, with the SAME dimensions as a 5G (and 4G), held 18" away from your eyes, would give you an image just as big in your field of view as a 24" TV 8 feet away. Not bad at all.
Then I decided to measure how big my current TV looks to my eye, compared with a ruler held 18" in front of me. At the two places where I normally sit, my ~21" TV looks only 1.25 to 2.5 inches across! It never seemed that small to me, but big-and-far (OK, medium-and-far) can give you the same image as small-and-near.
(Far is easier on the eyes, though, an hides the pixels.)