Budapest has a few vantage points available to view the whole city. Having been to Castle Hill, Citadella and St Stephen's Basilica I have to confess I loved the 360 degree view from the dome of the Basilica. It may cost money to get there (400ft or 2euros) but it is worth the climb.
Its amazing how much one can gleam from a 360 degree view, like the contrast in Bratislava between old town and new town and in Budapest, the difference between Buda and Pest. I'm now even more motivated to climb the South Tower of Stephansdom to scope out Vienna from above.
Buda and Pest are jam packed with buildings of different architectural styles, sizes and colours. One thing is clear, the city administration didn't have a standard to people had to stick to. The other interesting thing is the lack of skyscrapers.