I've been going to Beijing Delight for years at this point and they've always been a great value in terms of cost, quality, and flavor.
My go-to favorites include the typical General Tso's chicken, Orange Chicken/Beef and Crispy Beef, but I also like to mix it up with the Ginger or Szechuan Chicken, Mongolian Beef, one of the Egg Foo Young options, Moo Goo Gai Pan, or the Singapore Style Mei Fun.
I haven't tried many of the seafood options as I'm not a huge fan of it, but I'm sure I'd recommend at least a few of them if I was.
For appetizers, I'm a fan of the Dumplings (chicken or pork, steamed or fried... all options are good), Hot and Sour Soup, and Wonton Soup in addition to the usual Egg Rolls.
If you're vegan or occasionally fast from meat, dairy, and eggs, as I do, the General Tso's Tofu, Szechuan Tofu, Vegetable Lo Mein, Moo Shu Vegetables, Hot and Sour Soup, and Vegetable Rolls all make great options.
All in all, Beijing Delight is a great choice for a quick, tasty, and inexpensive meal when you don't feel like cooking yourself.