Considering the pattern of other high-profile XBox releases, you should be able to find it for $30 in a few months, especially at Best Buy (which had KOTOR for $35 less than a couple of months after release, even though the game sold well)... I remember seeing a bunch of relatively new games (mostly FPS) go down in price for weekly ad sales...
I think Microsoft probably makes deals with retailers to get them to lower prices for weekly ads, unlike Nintendo which is more stingy and you rarely see prices go down until forever (although Target had Pokemon Colosseum for $35 last week?!)...
Right now I'm waiting for The Twin Snakes to go down... Talking to some employee buddies I know Konami recently sent a shipment since my Target and Best Buy hadn't had them for a couple of months, so maybe they are gearing up for a sale...