The ex gf was a sushi conosur, so I've had a chance to sample several places around town.
Soma is probably the best I've encountered in Houston. The chef is an African American Britt (go figure), but the dude is a cullinary genius. Everything I've had there has been excellent.
Uptown Sushi, in my opinion, has the most creative rolls.
Sage 400 doesn't get a lot of press, but they always deliver on freshness and style.
There's a relatively new place called Zushi, at Memorial and Westcott that I can get behind. The menu is peaking. The head chef, Chris, studied under the famed founder of Nobu. If you ask him to come up with a unique specialty roll on the spot, he'll come through. Nice if you're bringing a little mamacita with you!
RA might be a bit overrated by the menu, but makes up for it with atmosphere.
Fish is pretty damn solid. I never have complaints (minus the wait at 9pm on weekends).
Has anyone tried Blue Fish House on Richmond (b/w Kirby and Shepherd)? I wouldn't say they are amazing, but they offer some good stuff for a really good price.
Myako is old faithful. You're never stunned, but you always know what you're going to get.
Rickshaw, Azuma, Zake, Taiko, and Kubo round it out. They do some things right.