Nessus Vulnerability Scanner is an awesome and powerful tool. It’s more comprehensive than out of the box Nmap. It orders vulnerabilities from Critical to Low. When you click on the certain vulnerability it tells you if there is an available Metasploit module. I have been able to exploit backdoors and find out if remote shares are mountable by an intruder. All in all the GUI makes it easier than Nmap. This might just be the best vulnerability scanner out there. There is a free Nessus Essentials one can download but any other version will cost money.