Favorite episode
To be fair, I haven't seen every episode, but so far my favorite is The Ski Lodge. The "bedrooms" scene is hilarious.
"I'm not gay, Guy!" David Hyde-Pierce was superb in this episode.
It's probably not very politically correct in today's society, but I always thought "Out With Dad" was the funniest. Nile's reaction to walking into the situation of his dad pretending to be gay and having to follow along with the pretense of being his boyfriend was hysterical. Again, David Hyde-Pierce was excellent.
My other favorites are the spelling bee episode with Frederick and any episode with Daphne's parents and brother. I know a lot of people hated Daphne's mother but I loved her. Anthony LaPaglia came under some criticism for his acting as Simon Moon, but I thought he was very funny.
Out with dad is hilarious. The most closed ended show in the entire series. Imagine Frasier becoming serious with that woman, Emily. How do you explain that Niles is in fact your brother and never was Martin's boyfriend? Oh and Martin was never gay.
The only irritating thing about the episode is how Emily is almost obsessed with getting her gay uncle laid. What was that? When her and Frasier emerge from a tour of the bedroom she sees that Niles is there acting as Martin's boyfriend and the look on her face was like a wife finding her husband in bed with another women. She is almost devastated. The direction went too far.