I am way into Frank LLoyed Wright's prairie-style architecture, the Unity Temple in Chicago being one of my favorites. I contemplated architecture school at the Frank Lloyd Wright School of architecture and almost got an undergrad degree in architecture; decided to go the finance route with my undergraduate degree instead. Probably a good thing; my interest is probably not significant enough to warrant a career in the subject (if you can't tell by now I'm basically interested in every subject under the sun).
In regards to modern architecture, Zaha Hadid is one of my personal favorites; she passed away recently. RIP.