If you are looking for a good meal, or are intending transitting the Canal, then anchoring off the Canal entrance is your best option. There is good holding, but the bottom can be a bit weedy at times.
Vic32 and Duke of Normandy at anchor off the canal entrance:
Adix at Crinan for the 2008 Crinan Classics festival:
View towards Crinan Harbour:
Crinan Canal basin:
In settled weather or if the wind is from the north, if you want peace and quiet Gallanach Bay will give you lovely views of Jura (though you'll still be able to hear the ceilidhs in the Hotel).
If you are heading north from Crinan you are sure to pass through the Dorus Mor (Big Door). Go with the flow in fair weather and you will have a flying start .. but try fighting the tide, especially with an opposing wind, and you'll have an uncomfortable fight on your hands: