So finally a chance to see more than the inside of Narita, a taxi and an office then?! Business trips can be a pain like that, I'd almost rather they were always somewhere dreary and grey that you wouldn't actually want to see anyway!

Plenty of good places to see dotted around at each major stop on the Yamanote line and easy enough to navigate that - until you get off at somewhere like Shinjuku station and need to find the right exit! I remember finding a decent vintage watch place off a side street in Ginza near the Sony Building, but it was definitely top end money there.

Jack Road in Nakano looks like it has some vintage Heuers in, though it will help if you like Skippers! http://www.jackroad.co.jp//X24_88.html

Some nice Speedies and a decent 6263 Daytona too.

This post gives you a decent description of how to get there, which is pretty important in Tokyo unless you read kanji very well: http://timetapestry.blogspot.com/2009/01/my-visit-to-jack-road.html