The TV series began with “The Adventures”, included “The Casebook”, “The Memoirs” and some feature length movies, but my favorite are The Return of Sherlock Holmes.
Both the book and the Granada televison series have a much darker, bleaker, and sinister mood. The novels because Sir Arthur Conan Doyle's son had died in the war and he was under immense pressure to revive his beloved character (Holmes) despite perhaps not wanting to revive him so much himself.
In the television series perhaps that brooding mood was due to Jeremy Brett's battle with mental illness after the death of his wife. Either way, the production is marvelous, and has my preferred Dr. Watson, Edward Hardwicke (who replaced David Burke).
Watch them all, however, to get a complete picture. They are available on DVD, netflix, and played fairly regularly on the Biography channel.