Well Metasploit 3.0 has been released for a while now. It is amazing the amount of change that it has undergone since its initial release. The Metasploit Framework is now a fully mature pen-testing framework. It really does rival some commercial offerings out there on the market today. This project also has quite a few nifty other offerings on the website. If you have not had the time or inclination to play with it, then I would definitely suggest you do so. You have all the tools contained within it to start your studies of system exploits, and all other associated fields, such as signature development. Give it a look. Better yet! Donate a buck or two to the guys to show your appreciation.