I like launch4j (to make the jar into an exe on windows) and NSIS for installation/uninstallation.
For linux, I like "makeself".
For Mac? I don't know. Currently I'm just using Java Webstart since I don't know how to make or test a Mac install, but I hear it's pretty easy.
Edit: (since you're quick on the draw there) I do prefer launch4j over JSmooth. JSmooth is easier, but launch4j can make your app look and act much more professional, and it's also actively developed, whereas JSmooth is not.