In my hometown of New York City, you can find good eats from just about every nation under the sun. And in the great city of London, that's just as true. While British food has come a long way in recent years—from gastropubs to molecular gastronomy—London is a cosmopolitan city of astonishing cultural breadth, and many of its real culinary treasures come from the rich cuisines of all corners of the globe. From hole-in-the-wall Vietnamese to high-end Italian, cheap Turkish to haute Thai, there's no country you can't visit—with just your Oyster Card and a sense of adventure.
Cheap Lebanese: Al-Waha
This restaurant (and several others on this list) comes recommended to us by my friend and colleague Fuchsia Dunlop, author of Shark's Fin and Sichuan Pepper: A Sweet-Sour Memoir of Eating in China and a truly accomplished food journalist. It's very moderately priced Lebanese restaurant in Notting Hill, with astonishingly bright, clean flavors and perfectly made meze. While much of the menu may look familiar—hummus, labneh, tabouleh—Al-Waha will leave you thinking differently about every one of these dishes.
Cheap Vietnamese: Song Que
Want noodles? Forget Wagamama. Fuchsia Dunlop called Song Que "cheap, crowded, and utterly delicious." The Shoreditch Vietnamese restaurant may be nothing to look at, but it's hard to mind once you tuck into a bowl of steaming pho (which Time Out London called "surely one of London's best")—any one of the 28 kinds on the menu. Perfectly prepared beef dishes are also worth a try.
Song Que: 134 Kingsland Road, London E2 8DY (map)
Cheap Turkish Kebabs: Mangal
Mangal on Arcola Street came highly recommended by Meaghan Fitzgerald of the Spoonfed London guide; this is a place for fantastic cheap Turkish kebabs—it's a no-frills place, but one that serves "the best of the best for kebab shops in London." Fresh bread wrapped around skewer-grilled lamb (straight off the charcoal grill) plus veggies, and spicy chili and garlic sauces—does fast food get any better than this?
Indian: Everywhere You Look
The Indian food culture of London is serious enough that it's impossible to pick one best restaurant out of the mix. A few that won't disappoint? The improbably named Hot Stuff on the cheaper end, with very few tables and a BYOB policy, and the Michelin-starred Amaya on the pricier end of the spectrum.
Fancy-Pants Thai: Nahm
Sure, it's possible to get a Thai meal in London for about one-tenth the price of Nahm—but the first Michelin-starred Thai restaurant in Europe, started by Australian chef David Thompson, is worth every penny. Everything from the the rethought Thai beef dishes to the incredibly intricate desserts is revelatory enough to have you forgetting the admittedly steep entrance fee—and the subdued elegance of the dining room completes the experience.
Fancy-Pants Italian: Theo Randall
Get a look at ruddy-cheeked Theo Randall and you might not envision him as a serious Italian chef. But Randall's namesake restaurant at the Intercontinental Park Lane was named "Italian Restaurant of the Year" at the London Restaurant Awards 2008, and for good reason. After stints at the River Cafe and with Alice Waters, Randall applies the most Italian principle of all—using local and seasonal products—to a British-inflected upscale Italian menu. Above, a perfect example; insalata di granchio, fresh Devon crab with mixed leaves, herbs, aioli, and bruschetta.
Fancy-Pants Sichuan: Bar Shu
Called London's first truly authentic Sichuan restaurant, Bar Shu serves firey dishes laden with Chinese-imported spices and chillies. The menu, devised in consultation with Fuchsia Dunlop, gives Chinese food fans a real look at one of the country's most interesting and vibrant culinary regions. You'll leave with your mouth tingling and your mind blown.