I usually start with Food Wishes, Serious Eats, or the New York Times. Julia Child for French food, Just One Cookbook for Japanese food. Budget Bytes when the bank account is looking a little thin. Dessert Person when I have a lot of time and want to knock the socks off my friends.
BBC good food. Usually a decent recipe.
Chef-wise I have a couple of Madhur Jaffrey books I use for curries, and then the flavour bible for cooking stuff generally that I’m comfortable with the base recipe for.