Don’t let the appearance of Robata scare you. It might be a little small, but it makes up for it in a big way with the food. And no need to order. Just say how much you want to spend and they'll take care of the rest.
I could people watch all morning at Tsukiji, world's largest fish market. The diversity of offerings can delight any seafood lover's cravings. Go early to watch the auctions. You won't believe the prices some of these fish garner.
If Sushi Dai's line overwhelms you, you really can't go wrong with any small sushi spot in Tsukiji. And if you want a real adventure, play stupid tourist and walk through the restricted areas of the market until a policeman kindly escorts you out.