Best ghost walk/tour in Edinburgh

I took the Mercat tour on the Vaults and it was quite good. There were some ghosties in that tour, but they have others that are specifically ghost tours. Here's their website. http://www.mercattours.com/scheduled-tours.asp

I had a blast with these tours: www.mercattours.com
There four different ghost type tours but they are all very similar with only minor variations. But they were fun enough that I did all the tours on three consecutive evenings; it was well worth the money.