Motijheel area - Nagar Bhaban (ie City Hall, headquarters of the Dhaka City Corporation). IMO this is a very well designed post-modern structure. At some later point I'll post additional pictures of some of the architectural details.
Motijheel area - Rajuk Bhaban (headquarters of the Capital Development Authority; photo from Wikimedia). This was the tallest building in Dhaka when it was constructed in the 1950s, and has some nice Art Deco-ish elements.
Motijheel area - Bangabhaban (Bengal House), official residence of the President (photo by Dhaka Tribune). I find this to be a very elegant example of Mughal-inspired architecture (the Supreme Court building being another good example). Some of original structure dates from the colonial period, but the current styling is principally a product of the East Pakistan period.
Bangabhaban by
Tanvir Mahtab, on Flickr