definatly fries, they do get colder quicker, but if i have ice cream, fuck em both, i'll find a little kid and say there full of magic, then steal his ice cream so i have 2 =)
Sneak a fry at the start, then I actually stuff my mouth with the burger and fries and chew it up at the same time. In the end though, the burger is usually gone first and I finish off the fries.
I alternate between the two, a bite of burger then a few fries. It varies which one I finish off last, depending on how good they both are and which taste I want to keep around in my mouth.
I'll start with some fries, then eat the burger with pauses for more fries. Typically when I eat I'll start with a bit of the side-dish (fries) as a warm-up before the main course (burger.)
I usually eat 1/2 my fries, 1/2 burger, 1/2 fries, 1/2 burger. Also, I eat my burger in a circle eating around the outside first and working my way in.