True, but in 2008, there will be 12 democrats defending their seats, and 21 republicans defending their seats. Its much more likely the republicans will lose some seats in the senate. Also possible retirees (D: Lautenberg NJ, R: Ted Stevens, AK, R: Cochran, MI, R: Domenici, NM, R: Inhofe, OK, R: Warner, VA) lean heavily to the republican side making many more republican seats potentially open.
The house, I would imagine, would go the way of the national election.
So, I see the senate staying democratic, and the house and president going to the same party.