Malaysia -- KL and Langkawi [Moved from International board]
You'll need to be more specific as to what kind of food you're looking for in KL/Langakwi for us to give you useful pointers. Malaysia's multi-ethnic (Malay, Chinese, Indian) and each has good restaurants/street foods/dining precincts.
For Malay, don't miss trying Malaysia's unofficial national dish - "nasi lemak" (coconut-flavoured rice, served with curry, chilli paste, fried fish, toasted peanuts). The most popular spot is Nasi Lemak Antarabangsa in Kampung Baru, a Malay enclave in downtown KL. My fave Malay restaurant in KL is Bijan, Ceylon Road. Out-of-towners (mainly Singaporeans) also liked Restoran Seri Melayu and Restoran Angkasa at the KL Tower.
There are good Chinese eateries all over KL, mostly offering Cantonese variety. If you do go to KL's very atmospheric Chinatown area - Petaling Street, make sure you try some street foods, e.g. wantan noodles from Koon Kee (started by an elderly couple who were refugees from wartime China 60 years ago), KL-style chee cheong fun (opposite Hong Leong Bank), Penang assam laksa, or some early morning dim sum from Yook Woo Hin, a popular 80-year-old Chinese teahouse/restaurant.
Another old Cantonese favourite is Yut Kee Restaurant at Jalan Dang Wangi, where dishes are cooked in giant woks atop huge charcoal braziers. It's been around over 70 years. Try their Hainanese chicken chop, beef noodles, curried chicken and roti babi (a kind of French toast, stuffed with minced pork & vegetables).
Some top-end HK or Singapore restaurants have set up branches in KL, e.g. Ah Yat, Pak Loh Chiu Chow and Crystal Jade La Mian Xiao Long Bao. Popular local Chinese chain restaurants include Esquire Kitchen (Shanghainese), Overseas Restaurant, Lee Ho Fook and Marco Polo.
Major food precincts in & aorund KL include: Jalan Alor (for street foods, bustling at night), Changkat Bukit Bintang (try Frangipani restaurant), Tengkat Tong Shin and Bangsar (lots of restaurants/pubs lining Jalan Telawi & Jalan Maarof).
For old-world colonial British-Malaya feel, try Coliseum steakhouse, or the Carcosa Seri Negara's Mahsuri Dining Hall.
For continental/French, some good choices are 3rd Floor at the Marriott, Le Bouchon, Le Bernardin, Cilantro
For more Malaysian eating choices, see
As for Langkawi, only 2 restaurants stood out in my mind: Barn Thai and Gulai House. Both offered mind-blowing cuisine amidst splendid surroundings.