I really like the recent movies with Robert Downey Jr. I've always enjoyed the books as well, but it's been some time since I've read them. Haven't seen the tv series yet.
The original stories. I also enjoyed the alternate reality in Without a Clue with Michael Caine and Ben Kingsley - oh, and the other alternate reality in Sherlock Holmes' Smarter Brother with Gene Wilder and Marty Feldman. I haven't seen the new versions yet (Robert Downey, Jr. and Benedict Cumberpatch), but everyone I know raves about them.
I haven't had a chance to see the RDJ movies yet but I did watch the BBC TV series and I am in serious love with it. Though I was a fan of Sherlock Holmes before as I did read the books, but it was really awesome to see it done in a modern setting like the BBC did.
I am just really hoping that with the new one coming to the US that is based off the BBC show in a way (with Lucy Lu playing the Watson character) that it doesn't do poorly.