I've included this section for people who develop websites for fun and/or profit. This may not be a whole lot of SUSEroot visitors, but it is a topic near and dear to me so here we go...
Quanta Plus is part of KDE's web development package. Quanta is similar to Macromedia's Dreamweaver for Windows. It includes a lot of advanced features including support for CSS and scripting languages such as PHP. Its tabbed interface lets you work on several files at once. Its built-in file browser supports ftp, so you can open and save to remote systems easily. If you're a Dreamweaver fan, Quanta is likley to be the closest replacement you'll find on Linux.
Another web development package similar to Dreamweaver is Bluefish. It is not WYSIWYG, but it does offer several time-saving wizards and auto-completion features. I never used it much because I was not able to open and save remote files through Bluefish, I had to save it locally, then FTP it with an FTP client. I also found it to be too much of a "hand holder"; all the wizards and tools just got in my way (I have similar complaints with Quanta and Dreamweaver), but if you like Dreamweaver, you'll likley find Bluefish to be a handy little app.
Nvu is a WYSIWYG web editor similar to Microsoft's Front Page. I've never used this one before, but if you're a Front Page (or other WYSIWYG) fan, start your search here.
I like to use simple text editors for my web development work, so I primarily use KWrite and Kate which are included in nearly every KDE package. They both offer the ability to open and save remote files and have fairly simple interfaces. Kate has a standard plugin that lets you use tabs to control multiple files, but using that plugin makes the icons in my toolbar move around, YMMV. Other popular text editors that might work for you include jEdit and gedit.
Popular CLI text editors: vi, emacs