OPINIONS PLEASE!

I'm a little overwhelmed today!  Among the numerous projects I have right now, I have taken on one of the most stressful projects, and that is the task of selling my house.  No realtor, just me doing all the legwork, which made sense financially.  It's all about the Benjamin's, right? 

That brings me to the reason for this post.  I need your advice, dear readers!  Send me an email, comment on this post, post to my Facebook Fan Page, whatever is convenient.  Here's my query...

Currently, I have black granite on my kitchen island and black tile on the other 2 counters.  Would you spend the money and install granite in place of the tile?  Is it worth the upfront cost without a guaranteed return?  Would this be a turnoff for you if you were househunting and the kitchen had tile counters and only a granite island?  Please share your thoughts if you have a moment. Here are some shots of my kitchen below. 

Do I spend the money or sell as is?