Focusing solely on food (but granted good atmosphere, company, and such):
1. Roan Kikunoi, Kyoto, chef Murata Yoshihiro, lunch
Why? Not only was everything totally spectacular, but we went in wondering if in fact the whole kaiseki thing was a bunch of pretentious nonsense, which is what it looks like if you read about it. Instead, we spent two hours eating unbelievable food and having Chef Murata chat, crack jokes, and entertain us -- and see us out at the door when we left. We came out thinking, "why have we never had this sort of dining experience ever before?" It was also my birthday, the kids were in school and dealt with, and that was the first time we'd had a chance to eat a really great lunch while in Japan... which helped, but the restaurant really is spectacular.
2. Kichisen, Kyoto, chef Tanigawa Yoshimi, dinner
Our first real kaiseki dinner, wife's birthday. Tanigawa did almost 100% of the service, chatted, entertained, explained, helped in every way, the ultimately gracious host. Every dish was exquisite, the linkages between courses stunning. Why is this not #1? Because we already knew it would be that good -- with #1, we really thought we might be blowing a wad of cash on something we'd end up chalking to experience.
3. Blue Ginger, Wellesley MA, chef Ming Tsai
I've eaten at better US fine dining restaurants, frankly, but the company has been almost invariably horrible. I love that Ming Tsai does interesting, complicated things and doesn't make a bit pretentious fuss about it. I also love that he's in the restaurant, saying hello at tables, using his celebrity status to make people have an even better time, rather than figuring he's above it all or whatever. The combination of kimchi and mayonnaise (kimchi aioli, he called it) with hanger steak was beautifully executed, and I still remember precisely how it tasted and felt in the mouth. Lord knows what I was supposed to drink with it -- it shredded the wine! -- but it was lovely food.
4. Oishii Sushi Bar, Chestnut Hill MA
Ate with a Japanese pal from Tokyo who'd been suffering for three years in Texas behind mounds of meat which he hates. He didn't want to eat Japanese food, but was polite about it. I made him order, so he picked a lot of things that seemed either so familiar and friendly that he couldn't pass them up or so peculiar (without being just bizarre, like Philadelphia Maki) that he couldn't resist. So we had a sort of back-and-forth between classic nigiri-zushi and things like uni-tempura. After the first three bits, my friend sighed and said, "that's very good fish." After that, we just sort of slowly munched along and ate and ate and ate. In the end, we didn't eat such a huge quantity, but every single bite was savored. Truly great: best sushi in America that I have eaten (no, I haven't eaten at Masa or the like).
5. Commander's Palace, New Orleans
Wife very pregnant with our first. We ate everything in sight, the service was excellent, and the food was the best we had in New Orleans --- and that's saying something. Not perhaps the best restaurant in New Orleans, and in some ways we did have better but chose the wrong dishes, but we had the best total experience here. The bread pudding souffle probably had something to do with it.