For mixed PC/Mac authoring and editing environments, CMS tools still present a dilemma. If you want to dispense with hand-coded HTML tagging in a browser, there are a wide variety of WYSIWYG tools that can generate pretty good XHTML (and some are migrating to XML). But the ActiveX-based controls leave out all the Apple people, and Java versions can be buggy and less conveniently configurable. Flash is showing some promise for those who don't mind a plug-in, but the tools are incomplete. Many European vendors are coming out with JavaScript+DHTML interfaces that we find quite slick, but most major CMS competitors have been slow on the uptake here. Our wish for the New Year: true, cross-platform, XHTML-compliant, super-configurable, crash-less authoring from any browser...
Check out Paul Browning's (U. of Bristol) excellent list of WYSIWYG editors