Some of my favorite restaurants in Tokyo include Brasserie L'Oasis (they have quite possibly the best bread ever), Roy's Tokyo Bar & Grill (their appetizers are insane! main dishes can be hit or miss though), and Ostu （オストゥ） (http://www.ostu.jp/), an Italian restaurant in a quiet corner of Yoyogi-park.
I haven't got pictures, but their website has a few.
An Italian/Japanese couple introduced my friend and I to the place, where the girls tried the set menu and the guys ordered a la carte. The restaurant itself is elegantly simple, and the staff are friendly and attentive.
Everything was fantastic. Of course, the price rather reflects it, but I definitely want to go back.
Yoyogi Matsuura Bldg.1F 5-67-6 Yoyogi Shibuya Tokyo
東京都渋谷区代々木5-67-6 代々木松浦ビル １Ｆ
every Wed., third Tues. of every month
Seats 20 people, non-smoking
総席数 20席 禁煙