DIEM  I have been using Rapidweaver for nearly three years now, and it is my primary tool for developing sites. It feature base is HUGE, and more importantly the community for development of plug-ins and themes is huge as well.

I find it odd to have it compared to iWeb, as that is for beginners, and this is not. Although user friendly, it does have a small learning curve, and should be placed in the pro-sumer categry, firmly between iweb and Dreamweaver. Spend the time learning, and you will see you can do most of the things discussed as downsides.  
(Version 4.1.2)

DIEM  doesn't get much easier than this...seriously. I used it, and 20 minutes later have cleared 20GB away of *stuff*.   
(Version 1.0)