I trained around Edinburgh last year for the FLM, and will be this year again - but I will again try and get long runs up to about 16 miles in the evenings.
I find the place perfect for evening running - especially when it starts to get light again. Water of Leith is good (when it's light), over Corstorphine hill, out to Leith around and back, or just round and round the town. I come from East London, so anywhere is more interesting - and I love having some hills to run up. I'm hoping to get a run around all six hills in sometime this year as well.
I tend to just set off from the centre, go round the meadows a couple of times, then keep running in a random direction until time's up!