While Android 1.6 is still writhing around in amniotic fluid, BGR had the nerve to publish shots of version 2.0 "Eclair", which doesn't even have a formal due date yet. They look great. Sorry 1.6, I'm already over you.
You're best off trudging through the entire gallery here, since not all the changes are all that visual, and BGR has annotated each shot with descriptions. That said, here are some of the highlights (keep in mind that some of these could be subtle features of Donut, or handset manufacturer add-ons — for all we know, this is Motodroid):
• The whole system feels much faster, especially the browser. Apparently it renders about as fast as the 3GS's, though part of that could be down to the hardware (What is it, BG?).
• The browser also gets double-tap-to-zoom
• Facebook friends are integrated right into the contacts system
• Voice control has been scattered through the whole system, and even gets its own dedicated dashboard
• There's an upgraded version of Google Maps, with layer support
• Native MS Exchange support
• There's now a unified email inbox
• A YouTube homescreen widget, which enables two-click uploads
• A "Car Home" app offers larger shortcuts for functions you might need while driving, as well as easy access to voice control