Vietnam - Ho Chi Minh City: what is the best area to stay?

We are planning a trip to Ho Chi Minh City and as we have never been there, we would like some tips on the best area to stay. We are thinking about going for about 1 week and we would like to be fairly close to the heart of the city or, anyway, close to a few main attractions and markets. We are not on a tight budget and we don't mind spending extra money if that means staying in a better area. Any suggestions?? Thank you!!