Well, this came as a surprise (srsly): NASA says it doesn't want to use Russian rockets during the multiyear gap between the Shuttle and Constellation eras. I've written about this, how NASA has sought a waiver from the government to allow them use Russian tech, despite a law disallowing it.
However, it's not that NASA won't use the Russians, it's that with the successful launch of a Falcon-1 from Space X, they hope to use U.S. companies instead of foreign agencies. That makes sense and I agree. I'm glad they're keeping their options open. That gap before we get the Ares rockets launched may stretch out, and NASA may need to have different avenues to space.