I'd say this is his best moment. The original historical novel -fictional characters placed into an actual historical landscape, taking part in real historical events - this is set during the jacobite uprising in 1745, where we follow the adventures of Waverly as he travels up into the mystical highlands of Scotland.
I have to confess I'm not a huge fan of Scott, but this is a pretty good read. He is, however, extremely guilty of being very longwinded, describing absolutely everything in minute detail (more so than Dickens), and the narrative can tend to swing off on tangents to tell you things that are really extraneous to, well, anything. In this way it does take quite a few chapters before anything of note actually happens, so you do have to have a high level of endurance, but you are rewarded, as when things kick off, you find you've been so absorbed in the minute characterisation of the main and supporting characters, you do really care what happens to them. PLus, after so many chapters of inaction, when the action happens it's all he more exciting.
If you only read one Scott novel read this one. And chances are you probably won't want to read another, but you will have enjoyed this. honest.