Web page building on the Mac has been a bit kludgy, until recently. Unless you wanted to just directly type html code and upload it to your webserver, WYSIWYG apps were not very WYSIWYG and difficult to use.
RapidWeaver is a relatively inexpensive app ($35) that has gained in functionality and features since its release. However, the knock on RW has been that it isn't so user friendly, support is not always sufficient, and purchasing additional templates and plugins can add up. [I have little experience with RW, so this is second hand.]
iWeb was released early this year by Apple along with its iLife suite. Steve Jobs touted its user friendliness, and many Mac users enjoy its easy learning curve. Unfortunately, iWeb was designed to work with Apple's .Mac service, though it is possible to design sites for non-.Mac hosts. The biggest gripes are in its extremely simple and limited features. And, geez, iWeb templates are absolutely horrible, with few other options available.
Karelia software is a small company that has been working on a user friendly web editor and were on the verge of being 'scooped' by Apple's January iWeb release before they could get their app to market. So, Karelia released a beta version of its web app - SandVox and has been working on it with beta testers for several months. I downloaded the first beta version of SandVox (SV) and found it unusable - completely. I came back a couple months later to see if it had improved and found that all of the major problems in the first version were gone, and other than a few interface issues and export problems - it was a much improved product. The feedback and responsiveness of Karelia folks to my requests, problems, and bugs were excellent. It's clear that they worked closely with all their serious beta testers, as it is now a fairly polished product.
Karelia finally released SandVox v1.0 today with two versions: Basic Sandvox - $39, and Sandvox Pro - $69. The pro version has some html customization features - and perhaps others, though I've not had a chance to mess with it much yet. SandVox' big advantage is in ease of use (easier than iWeb) without sacrificing functionality. I feel its interface is superior to iWeb. And frankly its templates beat iWeb's to a pulp (and you get more of them with the app).
SandVox also plays nice with .Mac as well as other servers. Uploading content from it in FTP mode is a breeze (though there yet may be a few bugs to work out with SFTP).
I'd like to compare it directly with RW, but haven't had time to do so as yet. From what I can tell so far, RW excels in customization and features. However, SV may be the easiest web page builder on the planet.
So, my recommendation is go and get SV soon. This program is ideal for folks with little experience on computers and the internet. And it's likely that Karelia will work hard to improve future versions, given their zest during product development.