I sat down to watch Caprica this week (Season 1, Episode 6) and I was so surprised to recognize the location where the Graystone cocktail party was held!
It's quite clearly filmed in Gatineau's Canadian Museum of Civilization!
The Graystones dancing (filmed in the great hall of the museum):
For comparison, here's a shot of that hall; note the columns and totems in front of the window:
Photo Credit: flickr user Яick Harris
This shot, a few seconds later, prominently features one of the museum's Inuit sculptures. If I recall correctly, it's somewhere up on the second floor.
I wonder when this was shot - it looks like summer outside, which means if the view isn't retouched too much, it was shot before this winter?