Geni offline or similare program

Hi,

I am just starting to build our family tree and I am looking for a help. As I tried many demo versions and online programs, I find Geni.com the best of all. I want to navigate, edit data, add people, explore hidden parts of the tree... in "extended family tree view", not just in "pedigree view". It is much less confusing for me, although I have to move right and left a lot :-)
The problem is that I want to do it (for now) completely offline. Does anyone know a program which support this feature? Preferably for Mac.

Katja