personally suggest "Seasons in the Park" at the peak of QE park. you can see the downtown from an elevated area. Food is good too. It hosted a variety of events including a dinner for Presidents Boris Yeltsin and Bill Clinton during the 1993 Vancouver Summit, the wedding reception for Vancouver’s singer/songwriter Sarah McLachlan.
The other suggestion is Le Gavroche. French cuisine. It is in a refurbished Victorian styled house. Good food and very relaxing and romantic.