We'll need a lot more detail to know for sure. Do you know HTML? If so, get Smultron or TextWrangler. If not, go with Kompozer or fork out some money for RapidWeaver or DreamWeaver (depending on the level of the site).
I use Adobe Dreamweaver. Very powerful. Depends how advanced you are with website creation. For me, the two main applications I use for Rapid Web Development are Adobe Dreamweaver (web creation) and Adobe Fireworks (graphics creation).
We'll need a lot more detail to know for sure. Do you know HTML? If so, get Smultron or TextWrangler. If not, go with Kompozer or fork out some money for RapidWeaver or DreamWeaver (depending on the level of the site).
Specifically, It's a basic personal style website with a flash based menu bar on the side. Nothing extraordinarily fancy. I ftp a server which contains the hosted html files, and replace them with updated html files. I want to ease the editing of the webpages, like adding tables, moving and adding pictures, etc..