Yes, it's true Jeremy Brett suffered from Bi-Polar Disorder and he also had heart problems. They were so bad the last episodes he played in (Memoirs of Sherlock Holmes), he was unhappy with his looks since the medication he was on made him retain water which in turn made him look "fat". He made it a point to be fully clothed in a jacket and all to help cover his "bulk". In those last episodes, he DID seem fragile, but that's because he was. Charles Gray (Mycroft) was called in to fill in in several episodes in which Mycroft makes no appearance in the Doyle stories.
Obviously, I think Brett is the ultimate Holmes (Duh! Bet no one coulda figured THAT out...), which isn't to say I don't enjoy Holmes' more recent portrayals (e.g. Downey, Jr. & Cumberbatch). Both actors bring a different part of Holmes to the screen that had never been explored before in previous incarnations. I think the Downey's Holmes see things as Holmes would, where his mind and powers of observation are always on. Cumberbatch brings Holmes' anti-social/sociopathic tendencies to the front while keeping in line with his true affection for Martin Freeman's Watson. While I will watch this new version, in the fall, I fear it will suffer from too many suit-fingers in the pot and ultimately fail.
For me, when I read the stories, I hear Edward Hardwicke's Watson narrating, Brett's voice for Holmes, Rosalie Williams' Mrs. Hudson, and Gray's Mycroft.
FWIW, if anyone is interested, Anthony Horowitz's new Holmes novel, "
House of Silk", which has been approved of as canon by the Sir Arthur Conan Doyle Estate is a very good read and it stay in line with the rest if the stories Doyle wrote both in theme and writing. I'm looking forward to more stories so long as they stay within the line so distinctly set down by Doyle.
-Jason