It really depends on Luongo's asking price. If its as steep as Canuck fans are predicting then Thomas makes a lot more sense. Hopefully he could give the reigns to Reimer in a year or two at most.
If, however, Luongo's price is lower I'd prefer him. He would solidify our goaltending longer and I'm not confident Thomas can keep up his level of play. Luongo also either gives Reimer more time to come into his own similar the Schneider situation in Vancouver, or he forces us to move one of him or Reimer (again, similar to the Schneider situation in Vancouver.
Tough call.