The best restaurants I've been to are:
Thai: Maenam, Urban Thai Bistro
Vietnamese: Phnom Phenh - outstanding chicken wings and for people a little more adventurous they use the same seasoning for their frogs legs
Malaysian: Banana Leaf, Bo Laksa King
Steaks: Gothams, The Keg
Tapas: Bin 941, Sardine Can
Boneta, Secret Location, L'Abattoir, Meat & Bread,
Sushi: Blue Water Cafe, Hapa Izakaya (Robson location), Guu, Bistro Sakana, Miku
Mexican: Salsa & Agave, La Casita
Pizza: Nicili Antica Pizzeria
Chinese: Golden Harbour Seafood, Kirin, Sun Sui Wah, Peaceful
There's just too many restaurants to name.