I have not yet tried Oceana - but that is one horrible name...
I have dined at every other place mentioned (and am shocked by
some being suggested as our 'best') and after much consideration based on your criteria the best 'WELL ROUNDED' option IMO is:
Divino's. Long local history, good and always changing menu, great location, great wine list, etc. AND Brad Pitt apparently likes it?!
Capo (although in Ingelwood and kind of small - but with Calgary's currently hottest chef), River Cafe (If your gal doesn't mind a 300m walk in the cold/snow in her heels), and Theatro (ambiance and location help it despite food that is a step behind some of the best) come in 2nd-4th.
Buchanan's (Steakhouses are not currently my interest for fine dining but some old-schoolers seem to think that is the only genre of Calgary fine dining...), La Chaumiere (not into French houty-touty-ness) and Rouge (All the way in Ingelwood...) are other interesting options.
I very much prefer places like Muse, Saint Germain and The Livingroom over places like Belgo, Chicago Chophouse, or Wildwood -
but i don't think ANY of them make the cut based on the stated criteria. Suburban location also basically disqualifies any choice - including Bears Den which is okay but far from great.
A number of the smaller places mentioned are FANTASTIC but are just too small or 'family-friendly' or 'old-school/family-owned' feeling to be the SINGLE pick. They are the types of places locals go all the time but lack that initial marquee 'umph' you need from ambiance and/or location and/or exclusivity, etc...
Claeren.