A buddy just bought one of the new Ruger .17 WSM rifles, and it does shoot "dime-sized groups" at 100 yards. He really likes it on crows, and right now the ammo is very available and not all that expensive.
Of course, the .17 HMR ain't bad either. One of the interesting things I've noticed is that a lot of shooters assume its bullet drift more in the wind than .22 Magnum bullets, because of the weight. In reality .17 HMR bullets drift less, because weight really has little to do with wind-drift. Instead the two determining factors are velocity and ballistic coefficient, and most .17 HMR loads beat most .22 Magnum loads in both ways.
