heat pumps

So I am getting a new heat pump (new heat and A/C system), and am a bit overwhelmed with picking what kind I should get.

I don't even know what all these mean:

-Air source heat pump
-Ground water source heat pump
-Earth coupled heat pump
-Direct exchange ground source heat pump
-multi speed or dual compressor heat pump
-comfort zone heat pump system

Anybody have one of these and any thoughts about its pros and cons? I'm willing to spend a little more to get the most efficient kind ...

Clearly, I need to do some major research this week.