Myself and Partner have been lucky enough to go on some amazing holidays in our 20's , trips to India, China, Cambodia, Vietnam, Iceland and a few city breaks in main land Europe. We are in our 30's and enjoy food and culture, not being ones to sit on a beach.
The trouble is we are lost for ideas. we want a main holiday in November budget around £1000 each, kids are staying at home with the GP, so we want some couple time too. Any ideas we are totally out of them. Not bothered if its somewhere hot or cold. Only area of the world I want to avoid is North Africa and the Middle East
Laos - Luang Prabang, plain of jars, - amazing temples and fabulous food Vietnam - I see you have been there before - but November is a good time to go trekking in Sapa. You can take the overnight train from Hanoi or there is a bus. The train is really slow and bumpy but it was good fun. Thailand - Bangkok, Chiang mai and then a few days relaxing on the beach. Burma - easy to get to now with e-visa - fabulous scenery, transport can be a bit challenging, amazing temples and Yangon probably has more colonial architecture than any other city in SE Asia. Not sure if these are within your budget as I live in SE Asia, but all pretty reasonable for accommodation and food once you are there.
How about India? You could do a tour of the Golden Triangle. When DH and I did this we booked with a local company who arranged everything for us. We gave them a budget of $50 per person per night and booked our own flights.