Greek Yogurt is awesome (Fage and Chobani are the two brands I've most frequently come across).

I enjoy mixing any of the following: granola, strawberries, walnuts, almonds, honey, raisins.

And if you want to mix things up wrt to your yogurt viscosity, try the soupier "Australian-style" yogurt from Wallaby. It's a nice contrast to the thick Greek-style yogurt.