I first found this book in HS. I took it out over and over again reading and rereading the short stories. Like most collections, some are better than others, but Asimov (the editor and writer of one of the stories) did a great job of picking a good collection. Years later my husband got me the book for the holidays and is now lent out becuase it's AWESOME!
Something to note- Asimov was a member of the Baker Street Irregulars, a (male) group of Holmesians who get together every year on January 6th (there is now a women's auxillary, but let's face it- the Master didn't like women all that much...or people all that much). In order to become a member of the BSI you are required to write an essay using information from the Canon (the 56 short stories and 4 novels that Doyle wrote on Holmes/the Master).
Asimov's edition to this volume is his entry. He writes a remarkable story about Moriatry and his doctoral thesis that I still can see reflected in new versions of Holmes (like the RDJr Game of Thrones) and gained him entry to the BSI and his BSI name- the Worm Unknown to Science.
If you enjoy sf/fantasy and Holmes overlap take a look at the new "Improbable Cases of Sherlock Holmes". It includes writers like Laurie King, Stephen King and Neil Gaiman as well as a large amount of Lovecraftian mythos. These two books have a special place in my collection because of their short story nature- Holmes was mostly in short stories and it is in this medium that he best shines.