Eh, no need to be that narrow: What fraction of all acquisitions end well for the acquired company? I'm sure it must happen, but (at the risk of availability bias) I can't actually think of any.
Depends on what you mean by "well for the acquired company". But if you just mean where the product (or possibly even the brand) went on to be successful, a bunch jump to mind: Pixar, Marvel, Google Maps, Ring, Zappos, Android, Woot!, Gatorade.