Which version of OS X should install on a 2006 MacBook? I have an old MacBook that I bought in 2006. I formatted and restored the original system. Everything was bad: I downloaded Skype, Chrome, and others, and every program said: 


  This software does not work anymore with this version of the operating system


(or similar)

So I installed a version of Mac OS X 10.6 (the one I got with my old iMac) and now it seems to work fine. Sometimes a few programs crash, and so I thought installing 10.6 wasn't the right way to go either.

What is the best way to handle an old MacBook with current versions of programs like Skype, Chrome, et cetera?
Depending on what MacBook version you have, you may be able to install different OSes.
However, what I do recommend is the best, and most stable OS that Apple has yet to ship: Snow Leopard, which is 10.6.X as you say. 
You should do a fresh install – not from a iMac CD, but from an retail Snow Leopard disc!
All apps but few still support Snow Leopard.