I've been getting this question often in the past few days:
Q:"How many people can a turkey feed?"
A:For a co-ed college group: I'd do 1-1.5lbs/person (depending on how much you eat)
For praxis/post-grads: I'd do 1lb/person
Does this sound like a lot? A turkey has lots of bone/skin/fat and other non-meat portions to it. In my experience with cooking whole chicken, I usually do 1.5lbs per person.
For a second opinion, check out the bottom right corner of http://www.butterball.com/en/index.jsp -- they suggest 1lb/person and 1.5lb/person for big eaters. I would err on the side of too much cause it's nice to have leftovers instead of running out.
Also keep in mind how much side dishes you are making when you estimate the food. My experience is there are bags and bags of leftovers taken home in gallon ziplocks
---Again, this is true if the turkey is good. A dry, bland turkey might be closer to 0.5lb-0.75/lb (child size portions)---