Tough question.  I DO prefer the GMC over the Chevy version this year.  The current Dodge looks good, and I've liked the current Ford F150.  All very close I think.  And it depends on color!  I don't like the Nissan at all, and I only like the Tundra over the Chevy but not over the GMC/Dodge/Ford.  And now there's an updated '09 Ford F150 to look at.  
 
So to answer your question, the one that looks best to me is:
 
NONE!  It all depends on the day and the color 

  I can't choose.   
 
Now if your asking about which one I'd buy, that's a WHOLE 'nuther story.  I never buy a vehicle on looks.