How do you actually pick a comfortable saddle?

I've got a few different ones for different applications (although 3 of them are SLR variants).

I can get comfy on all of them because:

• I've set them up properly
  
• I sit on them properly i.e. I don't 'sit'
  
• I don't stay long in one position
  
• I'm better than you*
  
  
  
  
  

*'you' meaning 'hippy'