Selenium Toolkit (preparing to write Selenium Tests)

What should you prepare when you want to write Selenium Tests in the form of Java JUnit tests?

I found that a few tools and urls can help to save your hair from getting too white:

• FireFox as the Browser with these plugins:
  • Xpather (homepage, extension)
  • FireBug (homepage, extension)
• XPath
  • XPath Tutorial Helpfull introduction into XPath
• Selenium
  • Selenium RemoteControl Has also subpages for Java
• IDE
  • Every IDE with JUnit-support is better than nothing, so just use your preferred IDE, as long as it has JUnit support.