The good Samuel Alito (who reminds me of Sandy Stern from the Scott Turow novels) will win confirmation without as much difficulty as many expect.
The O'Connor seat is not the crucial seat. Even if we have Alito, Scalia, Thomas, and Roberts, the other team has Stevens, Souter, Ginsburg, Breyer, and Mr. "Sweet Mystery of Life" Kennedy. This seat is not the one that changes the balance. It makes the middle depend almost entirely on Kennedy, that's all.
Where it's going to get ugly is if a Republican gets a chance to nominate Stevens' replacement.