Bottle shows are awesome.
The Doomsday Machine.
The Ultimate Computer.
The Immunity Syndrome.
The Corbomite Maneuver.
I think the reason bottle shows are
awesome is precisely because they do have limits imposed on them: there's something about being told "you can only use the regular standing sets, and don't go employing too many guest stars" which forces everybody to come up with a much tighter, less flabby final product. Whereas productions with a bit more freedom in those areas can sometimes over-indulge to the point of losing traction somewhat.
In my opinion, bottle shows have proven to be among some of Star Trek's most successful formats.