Don't you think that game developers right NOW are trying their best to create the one must have game for the PS3 to make it rocket to the top? You don't think that Sony would like to get Gran Turismo 5 (in development for over 3 years) out as soon as possible?
There's no doubt that many people buy PS3s for the Blu-ray player only and have no interest in games at all, just as Joeskie has demonstrated. And I'm sure that WB's announcement will have some people who have have been sitting out the format war jump in by buying a PS3.
But I highly doubt that there will be a large impact on gaming just because people who not interesting in gaming have bought a PS3--frankly, they will only make up a very small percentage. Besides, they're not interested in gaming.
So, the effect of WB's announcement on actual gaming? Minimal.