Whisky in Tokyo
Welcome to Tokyo, Pete.
My personal favourite for whisky shopping is a small shop in Shibuya called Kawauchiya. The sign is written kanji, but the shop is very easy to find. The block is Utagawacho 30. To get there from Shibuya station, go straight out of the Hachiko exit and take the road up towards HMV and Tokyu Hands. At a fork in the road you will see a koban (police box). Turn left at the koban and you'll find the shop immediately on the left hand side.
It doesn't look like much from the outside, but it has an absolutely tremendous selection of scotch and bourbon, including a wide selection of special bottlings. Better yet, the prices are competitive with the best prices you'll find in Japan, which as long-term residents here know are very reasonable. The shop's Irish and Canadian whisky selection has been steadily improving lately, to boot, including several offerings from Middleton. I picked up a bottle of Green Spot last week for about 4000 yen ($37). Other representative prices are:
Highland Park 12 at 4180
Highland Park 18 at 5200
Talisker 10 at 3700
Yoichi 10 at 4000
Elijah Craig 12 at 2000
Upstairs they have some very nice Tequila, as well.
If you'd like photo of the shop sign for reference, let me know. I can send it to you from my cell phone. Otherwise, feel free to tag along on my next trip there. I live close to Shinjuku and visit the shop often.