There are a lot of good places, but I wouldn't list Sushi Sake among the best. One that is often overlooked because it's in Round Rock is Origami. Fair prices and excellent food, too.
Sushi Sake is decent enough - good lunch deals. I usually eat there at least once a week since I work close by.
Uchi, hands down, has the best "creative" sushi menu and is an incredible overall experience. Price-wise, you can pretty much choose between that and any top-tier steak spot in Austin if you want to do it right.
Though I haven't been, I'll echo P/C on Musashino from everything I've heard.
Hole in the wall goes to Maru on Burnet & ~47th. Their spider roll is the size of an 8" sub.
Without a doubt, it's gotta be Musashino. A couple of years ago I took several friends from Vancouver there. They groused about how they were from the best place for sushi in North America and that Texas sushi had to suck. After their meal, they admitted that it was the best sushi they've ever eaten. I've been to Japan, and from what I experienced, Musashino could hold it's own. They get a special bonus for not bringing a spoon with the miso soup. I took a girlfriend there once and they looked at her like she was from Mars when she asked for a spoon. I laughed... on the inside.
tomo on parmer is great. I like it better than anywhere in Miami (including bond street, whether the Miami location or New York).
However, there is always that one roll at a specific place you can't get anywhere else.
We did Uchi. The wait on Friday night was only about 40 minutes and the food rocked our face off. When the kobe beef hot rock is the most pedestrian thing you order, the other items were exceptional... they had a yellowtail sashimi with asian pears, sliced almond that was to die for... and a black snapper carpaccio was exceptional as well. .
I'm very new to sushi, but I am hooked. I have only been to three places so far: Korea Garden on N. Lamar, Seoul on S. 1st, and Chom Son or something like that off of Wells Branch. All three were very tasty and seved beautifully. The yellow fin tuna was better at Seoul than Korea Garden, but other than that, it's a toss up. Both places were good. I want to try Chom Som again, because it was my first time and I didn't know what the hell I was doing.
I'm addicted now, so keep up all the great suggestions.