Hi Peat, hopefully I'm not coming here too late but last year I was asking the same question about Edinburgh as I needed a night in town at each end of a few days stay.
In the end I chose a quite remarkable place, easy walking distance (5-8 minutes) of the main central attractions and what can only be described as "your own playboy mansion in Edinburgh".
It's small-ish with not too many bedrooms and nothing is too much trouble for them when it comes to guests' comfort.
The name of the place is the actual address "No.1 Royal Circus" and although a little more expensive than I originally wanted to spend, it is really an amazing place. The decor is 100% jugendstil (Art Nouveau) and their basic philosophy is to make each guest feel like they are in their own personal town centre playboy mansion.
I have another thread somewhere on my original choices and selection process, I'll see if I can find it ......Edit:
Ahh that was easy ....... here's my original thread about Edinburgh.http://www.whiskywhiskywhisky.com/forum/viewtopic.php?f=273&t=5844
Page down to see actual links to my choices, maybe if Jugendstil is not their style, try the Bruntsfield which looks excellent. There are also some other nice looking recommendations from forum members.