Lukas Mathis puts the iPad 2 and new iPad screens under a digital microscope at 80x magnification. The difference is enlightening. Then he continues to put a whole slew of other devices under it as well. Fascinating. My favorites are the 3DS's top 3D display and the e-ink Kindle. Odd ducks, both of them.
Also notable is the Nexus One's Pentile OLED display. So far OLED hasn't gotten good enough that normal pixel orientations work well, so even newer Pentile phones like the Galaxy Nexus don't look as good as other displays with same, or even somewhat lower, pixel densities. It's easier to understand this when you see the pixel orientation up close.