I'll be posting something later today about what options you have when considering wysiwyg editors for Drupal websites but firstly want to make note that its very important to pay a visit to your input format options to make sure things are setup properly per project you work on.

You can typically access the input formats at 'admin/settings/filters' - a lot of people simply use the default Drupal inputs, which are great but when you use a wysiwyg editor some customisation may be required.

Specifically - with a wysiwyg (like FCK or TinyMCE), you may not want to let anyone but admins use the editor; if you're not adding new roles on your site for admins because just one person logs in as the site-wide general admin, there's nothing to worry about but if you have other people doing administrative tasks you may want to create admin roles and then assign the 'full HTML' input type to just a couple of them.

Once you've made sure that the right roles are configured to use the full HTML input type, remember that wysiwyg editors will auto-format line breaks, so to void premature line-breaks and funky formatting in general, be sure to turn off the line-break feature of the full HTML input type...