To me, most shows and movies are canon, a movie example is I don't consider STV canon, nor Spock's Brain, or that Voyager warp 10 episode where they evolve into newts. There are others but something has to be very low quality AND not be able to be explained away to not be canon.
TAS is semi-canon, and I also consider the better novels to be semi-canon... particularly the giant novels and some of the mini-series.
To bathe a cat takes brute force, perseverance, courage of conviction - and a cat.
The last ingredient is usually hardest to come by.
- Stephen Baker