The less you think about previous incarnations of Sherlock Holmes, the more likely it is that you'll enjoy the new movie which bears that name. If the notion of Sherlock Holmes baring his abs in a bare-knuckle brawl offends you, then "Sherlock Holmes" is probably not the movie for you.
But if you're looking for a fun slice of entertainment that incorporates some of the best known attributes of the Sherlock Holmes legend into a buddy picture with a lot of wit and action, then by all means, give it a shot - you'll probably like it.
Robert Downey Jr. is predictably strong in the title role, but the real revelation is Jude Law as Dr. Watson. Law creates a Watson that is very nearly the equal of Holmes in wit and cunning. I've never been a big fan of Law's (I can still remember how Clive Owen acted him off the screen in "Closer"), but if he keeps this up, that will change. Mark Strong is also quite good as the villain, and it's a shame that he couldn't have been saved for Professor Moriarty (assuming the film makes enough to justify the sequel that is clearly set up). The lead women in the movie (Rachel McAdams and Kelly Reilly) don't fare quite as well, but in their defense, the movie uses them primarily as foils to the two male leads.
All in all, I enjoyed it quite a bit.