Vitamix and Blendtec are the best "top of the line" blenders for frozen smoothies. Either will handle frozen fruit, whole fruits, nuts and greens if you decide to add them, with ease.
I considered both and purchased the Blendtec, which I love.
www.blendtec.com. My main reason for choosing that one is that it will fit under a kitchen counter, whereas the Vitamix will not. The Blendtec has more horsepower and a blade design that does not require a tamper. It works fabulously.
Here is a good link comparing the two:
The Best Blender Comparison: Vitamix vs Blendtec | Incredible Smoothies
If you're a smoothie junkie like me, and feel you can justify the cost, you will definitely not go wrong with either of these blenders.