Mostly I was working and attending representational functions in the evening, but I stayed downtown and did get a chance to see quite a bit just in passing.
My overall impression was that Berlin is very modern - clean, organized, cosmopolitan - and of course, very cold. ;)
Here's the Brandenburg Gate, right next to the US Embassy.
A statue in the Tiergarten park - I loved this park and as my colleagues can attest I wanted to spend every free moment here, wandering around.
Side view if the brandenburg Gate and the Reichstag
A Berlin Wall exhibit
Memorial to the Murdered Jews of Europe