There is an excellent LookAndFeel by Stefan Krause called XPLookAndFeel. It is limited to running on WindowsXP because of various licensing issues.

What I am about to show you is illegal. You should not do this, and you have been warned. Microsoft apparently holds copyrights on the icons in the XPLookAndFeel. So, that of course means its okay to copy it, but only to use it on XP (huh? what the? copy-what?). So let me repeat, I'm telling you not to do this. This is all theory and conjecture anyway because no one would do something MicroSoft didn't want them to do. I don't even know if this really works because I've never, ever, ever tested it because I don't ever, ever break the law. Who knows if it even works?

1) Start by downloading the archive labeled "zipped sources and the library" on Stefan Krause's website.
2) Extract the xplookandfeel.jar from the xplookandfeel.zip.
3) Expand the contents of this xplookandfeel.jar.
4) Back in the xplookandfeel.zip (not the jar, the zip) find com.stefankrause.xplookandfeel.XPLookAndFeel.java and extract it.
5) Edit this XPLookAndFeel.java as follows:

Find

public final boolean isSupportedLookAndFeel()
{
String osName=(String)(System.getProperty("os.name") );
return osName.equals("Windows XP");
}
Change it to:

public final boolean isSupportedLookAndFeel()
{
return true;
}

6) Compile XPLookAndFeel.java.
7) Place this new XPLookAndFeel.class in your expanded xplookandfeel.jar, in com\stefankrause\xplookandfeel
8) Re-Jar the expanded files (if you like).

Now you have a XPLookAndFeel that will run on any Operating System. Here's a screenshot of Netbeans with the XPLookAndFeel that I never, ever, ever took.