I'm currently in Bangkok after spending 3 weeks in Vietnam. I highly recommend Hanoi over Bangkok. Bangkok is cool, the food is good, alot of people speak English, and there's some neat stuff to see. However, it's also alot more expensive, you can't really walk anywhere as the city is so big and spread out, and the backpacking area is very very party orientated. There are tons of tourists everywhere, I'm not saying it's a bad or good thing, but I personally liked the lack of McDonald's and Starbucks in Hanoi. Most people I met throughout Vietnam said they didn't really like Bangkok too much, and said all they left with was the right to say "I've been to Bangkok." I'm beginning to feel the same. Hanoi on the other hand has just as good of food, its much cheaper, and has much more of a "backpacking" feel as opposed to Bangkok's touristy feel.