Hmm...I have 3 equal favourites, in no particular order:
1. pizza
2. fish and chips
3. kfc
Back when had more money, and didn't exercise much, I'd used to spend over $1000 alone annually on pizza, plus thousands on other junk foods. I've actually dreamed of fish and chips on several occasions! Hmmm...come to think of it, fish and chips is my favourite!
EDIT: Nowadays, I'd be lucky if I spent more than $100 - $150/year on junk food, and I hit the treadmill for 20 minutes a day. Still got alot of junk around the waist from the previous years of junk food mania though.