Obviously I'm going to rate P&P 5 stars, but this edition is also star-worthy. This series of Austen's novels, edited and annotated by David M. Shaprd, is absolutely indispensable to Austen lovers and anyone interested in the Regency period. Shapard's thousands of notes include information on everything from furniture and clothing to social mores and literary themes.
Do NOT read this edition if you haven't read P&P before. There are spoilers, and Shapard doesn't warn about them. He gives all-cap spoiler-alerts in his "Emma," so a quick glance at an annotation can warn a new reader not to read that particular snippet; but he assumes that readers of P&P are already familiar with the story. (Actually, he doesn't assume that -- he warns readers in the introduction that he'll be ruining some surprises.)