Back in the day, when I was in school studying architecture, Calatrava was my favorite. He is incredible for public works projects (stadiums, parks, bridges, subways/trains, etc), and pretty much horrible for home use. Sort of in the middle with a horrible-leaning bias for offices and the like.
But holy crap I love his style. (frequently based on animal skeletons, but not necessarily always in an obvious way)
L’Hemisfèric by Santiago Calatrava
Valencia, Spain
Hemispheric (via Goga_)