While the Landmarks Preservation Board can sometimes go overboard (Alan Ginsburg once puked on that wall, so it's a historic landmark!), we are definitely blessed to have a strong preservation group to keep our wonderful architecture.
The first building granted landmark status in Berkeley (as well as our only designated National Landmark) is the Maybeck designed First Church of Christ, Scientist
One of my favorite buildings is the Julia Morgan Theater, formerly St. John's Presbyterian Church. This is still a functioning theater, and is one of many structures that may have been lost to history without the Landmark Preservation Board (in fact, the fight to save this beautiful building led to the formation of the Berkeley Architecture Heritage Association.