In Unity, Maya and other programs, if you hit select an object and hit the F key, the camera "focuses" on an object: It moves the camera so that the object is in the center of the frame - much like the zoom extents selected does in 3ds Max - and also places a sort of pivot point for the camera orbit at the center of the selected object. Unlike Max, it keeps that orbit point even after the object is deselected.
ZBrush does something similar, but it simply orbits around whatever point on the surface you click on.
This is probably the number one thing I wish I could bring from other 3D programs into 3ds Max. It seems like standard practice for most 3D apps, and my workflow feels slightly hampered for not having it.
Thanks!