What is the best webcam and software for video conferencing calls?

Also by the way I have an HP DV6000 laptop and I am about to get the the iMac I7 quad core 27 inch and my parents have a pretty decent off the shelf HP desktop.
My parents moved 700 miles away and my Dad has terminal cancer. I am looking to get the best webcams on both ends and best software with my own money so that I can be as close to them as possible.

They are retired in the Carolinas and I am living in New York City and I am tech savvy I just don't know where to start. I got hooked into those Cisco tele-prescence commercials but that stuff costs like a billion dollars.

I just want to know how to get live streaming video/audio in HD if possible from one comp to the next. I have the money and drive to make whatever possible. I just don't want it to be blocky or slow or whatever.

Is there anything close to what they show on the movies or those Cisco commercials where it is like a live one to one with quality and speed? Thank you so much in advance for your help.