RapidWeaver by Realmac Sofware is a WYSIWYG web editor that we like. If you're unfamiliar, it's a super-simple editor that features iLife and .Mac integration, flash photo galleries, an SDK and so on. Version 3.6.4 offers Leopard compatibility.
Realmac also announced today that Rapidweaver 4.0 is under development. It will be exclusive to Mac OS 10.5 and a free upgrade for registered users. Cool! In fact, you can get a sneak peek of of RapidWeaver 4.0 at London's MacLive Expo at the end of this week.