Maulden Woods. It's already rather spooky at both ends of the day, I could add new "ghostliness" ...
Your house ;p
I'd like to haunt my old boss's computer. It'd be a case of Didge ex machina rather than Deus ex machina.
My ex-wife's home.
IF I was a ghost I would probably do something completely immature and haunt the Dallas Cowboys locker room! Or something like that! LOL!
Hotel Del Coronado. It's one of my very favorites places, I have many memories there.