Im not really sure what my ultimate career goal is since i cannot conclusive say what i will make a career of,?

but anyway to make a long story short, since i can only know so much up to a certain point with absolute certainty, would it be best to plan for retirement with a 401k assuming that a future employer will offer it and that they will also make a matching contribution or would it be simply best to do a roth IRA? between a 401k plan assuming that an employer provides it and also assuming that not only will they match it but at the same time one can say to oneself this is my career from now on, an a roth IRA which one is truly better in the long haul for people who cannot establish absolutely certainty about their career goals in life? which is truly better for people who are extremely serious about retirement and who truly are even more serious about not touching their money until they are truly ready to retire alltogether in life?! can a financial expert please tell me their opinion.............. thanks.