SharePoint is a great product, but one area where it really lacks is in it's Rich Text Editor.  It doesn't work in anything but IE, and doesn't include an image upload feature.  With a little digging, I found this free replacement from Telerik:

http://www.telerik.com/community/free-products.aspx (ASP.NET RadEditor for MOSS Lite)

Installation is non-obvious in the normal sharepoint way:

• Run stsadmin.exe to install a wsp
• Deploy in central admin
• Turn on in site settings -> site features
• Restart IIS.

It comes with a chm help document (which if you’re using vista you’ll need to unblock to view) that outlines the steps.  To turn on for a Wiki, follow the steps in ‘Using RadEditor in List Items’, and you'll have a much more usable SharePoint Wiki!