Black Hill is great, but only when it's dry, or frozen.
There's a lovely run from the foot of West Kip down to Green Cleugh. Gets nice and rocky near the bottom.
There's some man-made (okay, yoof-made) stuff in the woods on White Hill. Some of it's too technical for me. Outside the same woods there are some great, very steep, grassy descents to just behind the scout camp.
There are various descents off Capelaw.
There's a nice descent goes round Castlelaw, leaving the main track at the cattle grid.
There's a huge piece oh singletrack we call the Nail Trail that goes from near Red Moss down to the middle of Balerno. The gradient is very gentle (you have to pedal the whole way) but it's very tight and twisty through the trees and goes on for ever.
There's a good wee descent off the top of Bells Hill.
Loads more stuff too. We should have a big STW ride up there one evening sometime, say early September.