Robert's Rebellion is the obvious choice, but we do already know the basic story and some of the detail. Would prefer to see something where the turns wouldn't be so predictable.
I'd like to see the Age of Heroes and the Long Night. It's a fairly blank slate to work from, and there are so many options to do things a little differently to ASOIAF, in setting and style.
Trouble with Rise of the Targaryens (I assume Aegon's Conquest?) is that Balerion tips the scale so far in Aegon's favour, that no one provides any real threat to him.