Intelligence is still recognized comparatively, usually related to something like the capability to resolve difficult or ambiguous problems with similar or greater effect than humans, or can learn and react to dynamic environmental situations to similar effect as other living things.
The second part is an important milestone for me. Take the Big Dog - a marvel of robotics in itself. If it interacted with environment and its operator on a level that real dogs interact with environment and their masters, we would have a real breakthrough. An essential thing would be to make it learn new tricks, like a dog learns, instead of programming them in.