S&M is a fantastic example - I'd probably point it out as Lars being at the top of his game. I'm a huge fan, and have played along to more Metallica tunes than most people have spoken words - but even I must admit his playing has declined in recent years.
At the last 2 gigs of theirs I saw he was awesome, dynamic, driving - however when I watch videos of him that the band upload through their website/youtube I can't help but grimace a little occassionally.
But that being said, he's one of the 2 guys who wrote the vast majority of those awesome songs that I, and millions more, love. So what if he's getting old and out of practice! Still love the guy!