Touching the metal bit of the case before hand is a good idea, doesn't need to be earthed. Doing so equalises any static electric potential between you and the case (you+ case- / you- case+ to ++ / --). If you were handling stuff like that on a daily basis then I would say a mat and strap is worth it. Just don't use a stick of RAM as a lightning rod and you should be fine.



always wear a antistatic strap now.