I just discovered something that isn't mentioned here and I though I would share. My NetBeans configuration (Tools >> Options >> General) showed my browser as "Default System Browser" and it seems that it did not pick up Chrome as my default browser. Needless to say when xdebug was called it did not know which browser to open. I changed it to my only other option which was Internet Explorer and voila! Just the basic configuration of downloading the correct xdebug file and setting the path and the other 4 common options in the "correct" php.ini. There is an option to edit the list to include other browsers as well, but only one at a time.
My system is windows 7, xampp and the latest version of netbeans and xdebug as of december 2011. This flags will also help other users with a similar config find this post. I hope it helps.