KompoZer is an attempt to rescue nvu from its current state of bugginess and general lameness. Thank you to an alert reader for mentioning this to me.
Although currently at version 0.71 this is a far more functional and robust program than nvu.
This is the closest thing I've found to an open source replacement for Dreamweaver but, frankly, unless you're seriously determined to not pay for your software, I would use a commercial program such as Dreamweaver, Coda, or Sandvox.