My all time favorite dish is the salmon on fire; this is delicious and such an amazing presentation! The salmon literally comes to your table over flames, which you can blow out once it's been seared to your preference. Every time I order this I get stares, and at least someone asks what it is! I love the combination of the seared marinated salmon, toasted garlic, and raspberry sauce.
Another favorite dish is the wagyu beef on a hot stone. The beef comes rare in a marinade, and you cook it to your liking on a searing hot plate at the table. This is also a dish that attracts a lot of attention!
I usually finish with a selection of sashimi which varies based on what they have, but I generally get some variation on west coast oysters, uni, white salmon, and spicy toro gunkan. Everything is always incredibly fresh, and presented beautifully on a bed of ice.
I also love the creative desserts at Oishii; several of them are light and reasonably healthy like this frozen melon with gold flakes and white chocolate shavings.
I've been to Oishii many times over the years, and it never fails to blow me away. If you haven't been, I highly recommend checking it out!