Well, somewhere without a live band would be good
Otherwise, somewhere not a stupid distance from Waverly, and hopefully not so loud that we can't hear each other speak
I'm hardly an authority on Edinburgh pubs, but here's a few thoughts...
Malt Shovel, Cockburn Street
Cask & Barrel down on Broughton Street
The Cumberland, down on Cumberland Street
Quite like the idea of the underground streets place - Sharon and I went to Mary King's close a month or so ago and found it fascinating