The 2002 Napa Valley Cabernets, always showy, are more than living up to their early promise. They have aged beautifully; the best are dense and generous, with a broad array of flavors and supple texture. Adding to the appeal, many can be had for prices lower than when they were released, something to consider if you missed out early on or want to acquire a mature wine that still has room to grow. Wine Spectator's James Laube explains.