The one in the Bellaire area is called Planet Zero. It's more of an arcade place, they had Street Fighter IV cabinets, but they have monthly anime parties with cosplay and have a lot of imported Japanese anime goods, and some game goods. They're not that great for import video games to PURCHASE however, just for trying out at the arcade or for buying some exclusive anime imports.
There's a place called Microplay in Webster that carries used games and anime that may have some imports, but not a lot.
I've yet to find a good import store in Houston as I think the Japanese population is low and there isn't much market for it sadly.