we went to the zoo last Saturday, took the safari bus to the top of the hill(it is a steep hill), we were there for 4 hours and didn't see everything - the penguins were great, I felt very sorry for the polar bear it looked very agitated/unhappy. after 4 hrs there my legs ached for two days and that was mostly downhill walking! (I cycle loads so I am fairly fit).
We took food with us and got coffees to takeaway, and icecream for the children(even though it was frrrreeezing).
the play area in the Prince's Street is good, (ice-cream there is at least a £1 cheaper than at the Waverly end of the gardens!) and just up from there on Prince's Street is a church with a fairtrade cafe at the back, child friendly and serves wine etc.
We took food with us and got coffees to takeaway, and icecream for the children(even though it was frrrreeezing).
I would usually recommend the museum of Scotland, esp if it is raining, though they are doing some renovation work, the new bit is still open and has loads to see - is free (again food there is very expensive imo).
the National Portrait gallery is good too, though I haven't been in a while, it has a good cafe, but it does get busy.
I would avoid Prince's Street for shopping, it is crap, long, tourist filled and has some shops twice! bit grim imo.