Located at the top of Dougenzaka, Legato (owned by the Global Dining group) is one of the mainstays of Tokyo ex-pat dining. I've "done" Legato at least four times during my time in Tokyo and I've never failed to have a good time there.
It's not because the food is so good, because it really isn't anything to write home about (except for the 50 day aged steak - yum!). The wines are another matter however and on a recent visit for dinner on a Saturday night with friends from overseas, our attentive maitre d'hotel, Nabil, made sure that we were fixed up with a lovely Aussie Pinot Noir.
It's a great place for a reasonably priced (well for the food at least) night out with gaijins who aren't too fussy about insisting on going somewhere from the Michelin Guide. I'd advise you to start with a nice drink and take in the view at the bar before you go to your table.
The 200 gram aged steak. The trimmings of mashed potato and a few scraps of mushroom didn't rock my world, and it comes with no sauce (and none is offered). However the meat itself is basically to die for so you don't need anything really other than a bit of pepper with this one...