For 100 yard shooting, and you don't want to break the bank, a Nikon Pro Staff in 2-7x32mm would do you fine. If you want to spend some money, the Nikon Omega, or Bushnell 3200 with Rain guard, there are lots of good scopes out there.

The thing I always keep in mind is, for stalking I want a real low power like 2&3X. For sitting, at least a 7X as that would do you to 150 yards with little problems. Then I was a scope with good eye releif, 3.8-4 inch is what I want. Last I want good clarity, a good parallex, and a life time warranty. That was why I suggested the Nikon Pro Staff. There are better scopes out there, but none that I need for the money.