A meta example, the first transformation scene. This movie depicts a very agonizing transformation, with David's body gradually becoming more and more wolf-like in appearance until just flat-out looking like a deformed husky. Each shot adds more details to the transformation, with very few cheap tricks such as jump cutting. The result is the greatest werewolf transformation bar none. And the kicker? This was all done without CGI.
The attack in the tube station. Perhaps the best directed scene of Landis' career.
A dark one, but David's second rampage. He only kills a few people directly but in the panic, cars crash, people get trampled and run over. The fact werewolf!David avoids getting killed in the chaos is awesome enough.