“The Celler Grill W” (http://www.cardenas.co.jp/shop/restaurants/w-omotesando-the-cellar-grill.html), wine bar, at Omotesando. Very reasonable wines, choosing bottles by yourself. You can buy the bottles and pay 500yen for glass, then drink. It is said the price of bottles is same as retail price at stores. Their food is better than average.
“Nikka Blender's Bar” (http://r.gnavi.co.jp/g784705/lang/en/map), whiskey bar, B1F of Nikka head office at Omotesando. Nikka Whiskey is very old whiskey brand in Japan, and the quality is excellent! You can enjoy many kinds of molt / blended whiskeys here, those are not sold at other places. I would recommend "Tasting Set", composed by 6 glasses.