These are the popular options for coders who don't mind hand-crafting the HTML:
BBEdit (old school, lots of fans)
Coda (mainly used by PHP fans)
TextMate (mainly used by Rails fans, I use this mostly)
MacVim (I like vim)
XCode (it's nice, but it's a bit clunky for HTML)
NetBeans (slightly clunky, mainly Java based but does other stuff)
Eclipse (plugins for everything, slightly clunky, mainly Java based)
DreamWeaver is not a programmers tool, it's for basic web building. If that's what you want to do, there's also RapidWeaver.
I also recommend ColorSchemer Pro -- it's on the app store right now at a discount (about $10).