Well telling someone that you have never had problems without also telling them about the potential for problems to arise is not good advice.
OP it might do you well to try and determine why certain packages are being held back and then determine if forcing the install of these may cause you problems.
I would look in the beginner section here and see all of the recent posts in regards to metasploit. That's should take care of your question.
See also
http://www.linux.com/archive/feed/48910 for more general info.