Who played Niles Crane in 'Frasier'?

In which TV series is Fox Mulder a main character? Who played Dana Scully in 'The X-Files'? In which TV series is Dana Scully a main character? Who played Frasier Crane in 'Frasier'? In which TV series is Niles Crane a main character? Who played Daphne Moon in 'Frasier'? Who played Khadijah James in 'Living Single'? In which TV series is Khadijah James a main character?