How do you say 'home is where the heart is' in traditional Chinese characters?
There's a few different ways to do this.

Aurus Huang already suggested 


  心在哪裡，家就在哪裡。


above.

Baidu gives us:


  心之所在即為家


This Baidu Zhidao question also gives a lot of examples:


  心中向往的地方就是你的家





  家是心之所在





  心所在的地方是家。


but my absolute favorite, and honestly the best translation of this phrase has got to go to:


  心所向，家所在。