I was doing some research for my upcoming talk at the FME User Conference later this week, and came across a really interesting blog called Digital Urban - lots of great stuff on 3D modeling and visualization, and related items.
A few examples of interesting posts include this one on a game called Prototype for which they are building some extraordinarily detailed and realistic models of New York City. Check out the following video in particular - the second half is where you really get to see the models they are building (I recommend the high definition version).
...this one on the Da Vinci Tower in Dubai, in which each floor can rotate independently, and the tower includes built in wind turbines which power it and neighboring buildings (there's a high resolution version of the video here).
... and finally I really liked this HDR image of New York by Paulo Barcellos, funnily enough the second time I saw a reference to HDR imaging today, a term I hadn't come across before but there's a good explanation at Wikipedia.
There's lots of other good stuff at Digital Urban too, so check it out!