Here they are:
1) Cake or Pie: PIE! Not that there's anything wrong with cake. But pie is better. My father used to say "Cookies are for children, cake is for ladies, pie is for men!" And pie is for breakfast too, where I come from.
2) Train or Airplane: Train
3) Mac or PC: PC
4) Univocal or Equivocal: Equivocal. I guess.
5) Peter or Paul: Peter
Try not to pull on the big cat's tail when you answer. :-)