I was most impressed with Ch. Marquis de Terme in Margaux from the perspective of viniculture. They are doing some fascinating things, experimenting with a variety of fermentation and aging methods that I hadn't seen before. Astonishing for a property whose terroir would seem to guarantee excellent high-priced sales without reliance on new techniques.
I'd also strongly recommend taking day tours on both the left (Pauillac, Margaux, St Estephe) and right (Pomerol, St Emilion) banks of the Gironde. And make sure you visit St. Emilion the village. Ophorus was an excellent tour company for us. I'd also strongly recommend the wine shop Le Cellier de St Emilion on Place de l'Eglise Monolithe in the village. They have a good variety of wines to taste in a Cruvinet, and their wine retail pricing is very fair. Ask to taste the Chateau Martet.
For wine tastings, I'd also recommend the Musée du Vin et du Négoce de Bordeaux in the city of Bordeaux, where they'll serve you a range of wines that you're unlikely to encounter outside of the city. A terrific place to visit for anyone who loves wine.
Burgundy? I'm useless; sorry.