Did I miss the news somewhere that GoogleMaps got a big UI update?
The largest noticeable difference is that when you "zoom" it's first just increases the resolution size of the current layer of tiles, and then replaces them with the actual higher-resolution (new) tiles as they come back from the server. The effect is a kind of disjointed 'popping'. I like the idea that the zooming is better, but I don't think they should zoom the text - which makes the popping more apparent.
There are other little flavorings are Web2.0-boxing of the 'Search the map | Find businesses | Get directions' tabs.
Ahh, I see there was a GoogleMaps Blog post titled, appropriately "Zoooooooom!".