I've been to Vietnam 5 times and will be going again in March. The places you MUST see are Hanoi - the old quarter is fascinating plus visit the mausoleum of Ho Chi Minh - and the water puppets. Shopping is fantastic and the city is really beautiful with the french influence in buildings and food. Hoi An is also a must and an incredibly pretty place - try to get a hotel on the beach - they are superb. Nha Trang is also great - but you really need only 2-3 days max to see everything.
Saigon also a must - very busy city but fabulous for shopping. Do a one day tour on the Mekong Delta and a one day tour to the CuChi tunnels - both a must on the agenda - book these when you are there at the Sinh Cafe (everyone knows where this is) and it is much cheaper than through your travel agent.
It is a magical place Vitenam - and you never go just once...!
I have just came back. I had a week in Danang and a week in Ng Trang. Both were Luxury Link Danang was not up to Luxury Link standards. I have stayed at the Ana Maranda resort twice it really is very nice and while I was there I went to see the Hide Away which was out of this world . The people are great the food is fantastic. Take plenty of sun screen as the stuff you buy there is faux so beware!!
We've been to Nha Trang (Ana Mandara through luxury link) 6 times....each time has been great! Stayed at the Hideaway twice. The first time was 3 nights....the second time was for a week. My husband doesn't 'sit still' for a week....and basically that's what you do at the Hideaway. I love it....can read and watch the ocean for hours on end. Our next trip to NhaTrang we'll skip the Hideaway....and just stay at Ana Mandara.....he walks the beach, the town, different restaurants.....the mocha cake at La Louisianne is outstanding!!
Try Dalat next time instead of Danang. We've stayed in Dalat before Six Senses property opened....stayed at the 'palace' (I think) hotel....absolutely wonderful. Haven't been to the Six Senses property yet....but I vouch for the chef, David Thai....we've followed him from Ana Mandara to the Hideaway and now he's in Dalat. I'm happy to say we are the 'faux' grandparents of his 3-year old daughter Ana.
Love Vietnam....wish we could live there for a while.