If you want a peaceful day out of the busy city, Highgate doesn't really feel like London. The cemetery is interesting and peaceful, there's a tour of the old half which is definitely worth the money. Karl Marx, among others are buried there.
Old townhouse style building set in front of juxtaposing high risers makes for an odd placement, but internally it's a quirky spectacle. One half is dedicated to the sale of antiques - anything from old door handles to hallways lined with hunting trophies. The other half is a relaxed bar and hidden gourmet dining area constructed of similar furnishings [all for sale too]. Even if you don't wish to spend £'s, a walk around the place is advised.
A small place to eat with great vegetarian/vegan food just off Camden High Street. This place does an amazing buffet at a great price, as well as serving reasonably priced tea and juices.
Good, progressive, solid, forward-thinking place. And run by the warmest, most intelligent and inspiring people to be around. Always a humble, fulfilled visit. And whilst in the area, best to visit next door to Hannah Barry's gallery for more wonderful work.
The many book stores dotted along this strip can provide hours of inspiration. Aside from those selling new books, several specialise in second-hand and antiquarian books.