Marben (newly revamped), Le Select (French bistro), Victor and Blowfish (there is plenty of cooked food on the menu in addition to what was newfangled sushi when it opened) are other somewhat fancy options near/on King West. I'm suggesting them not because I consider them fancy fancy (for fancy fancy, I agree w jlunar's recs of Splendido or George, or would recommend driving uptown for Auberge du Pommier), but because one person's "fancy fancy! " might be another person's upscale/moderate.
432 Wellington St W, Toronto, ON M5V1E3, CA
488 Wellington Street West, Toronto, ON M5V 1E5, CA
30 Mercer Street, Toronto, ON M5V 1H3, CA
Splendido or George would be my fancy-fancy rec, but neither are King West.
So, on King West:
Lee Lounge might be open by then. Not sure. Susur back in the house and all that. Less formal dining, I'm going to assume.
I love Buca, but it's trendy-fancy, not fancy-fancy. Loud. Good pig's ears. Pastas are okay-to-good, but expensive.
Jacob's & Co. - Steak house though.
There are maybe a couple more. Can't think of them at the moment.
111 Queen Street East, Toronto, ON M5C 1S2, CA
88 Harbord Street, Toronto, ON M5S 1G5, CA
Jacobs & Co
12 Brant Street, Toronto, ON M5V 2M1, CA
601 King St W, Toronto, ON M5V1M5, CA
604 King St. West, Toronto, ON M5V 1M6, CA