Light Chocolate desserts such as mousse:
Italian light sweet sparkling wine (Asti Spumante)
Young Sauternes
Unfortified sweet wines from the Muscat family
California Orange Muscat (Quady Essensia, which is great with chocolate/orange desserts)
California Black Muscat (Quady Elysium)
A lush, ripe California Cabernet or Merlot 

Medium weigh desserts such as flouless chocolate cake:
-- Muscat de Beames-de-Venise
-- Muscat de Rivesaltes
-- Muscat vins doux naturals from Languedoc-Roussillon
-- Muscatels de Valencia

Heavy, rich chocolate desserts like a rich double chocolate cake or chocolate torte, truffles
Ruby port
Ten-year-old Tawny port
Australian liqueur Muscats
Malaga

The Experts at FoodTv.com Suggest...

Not Sweet Chocolate
The Chocolate: Chocolat Grand Amer, 85% cacao, from the Paris house of Michel Cluizel

Actually, all of the wines in my tasting went well with this super-dry chocolate, which has a kind of coffee-bean bitterness about it. When chocolate is this austere, it's an ideal backdrop for almost any wine. I'd even go so far as to say that rich California Cabernet would go well with chocolate this un-sweet. My favorite sip with it, however, was a spirit that went poorly with the sweeter chocolates in the tasting:

The Wine: Bas Armagnac, Cerbois

Wine maker: Cerbois
Price at review date: $25 for 350 ml
Region: Southwest France
Country: France

This brandy from southwest France has a gorgeous nose of vanilla, nuts and earth, followed up by a palate that's unusually silky and gentle for Armagnac. The touch of sweetness is just enough to get it over the chocolate hump. The result is two austere tastes playing a lively duet; the flavors of neither get canceled out. This is a serious, sophisticated, thoughtful match--a good one for a pensive Valentine's Day, for lovers who prefer subtler pleasures.

Review date: February 1999
Reviewer: David Rosengarten
Distributor: Winebow, NYC