For the purposes of building muscle mass, olive oil is fine. In terms of overall health, however, you want to make sure you are getting your omega-3s and some quality omega-6s. For omega-3's, fish oil is best bet. Borage oil is a nice source of good omega-6s.
In general, Americans get too many of the wrong kind of omega-6s, but that in no way obviates their role in our diet.