Although I have very little medical credentials (only in certain states, and those not even part of this country), i would heavily endorse the no-pop routine. I can't think of something more corrosive to put into one's body on a more regular basis than pop. (this is food-wise, mind you)
Of course, if your beverage of choice remains a liquor and pop concoction, I would advocate putting the pop in the glass first, then the liquor, in order that you may, by this method, actually be making a drink better, wherewith by adding pop to liquor, you are in fact making a perfectly good drink worse.