"Ammo is a nice gesture, but people can be picky about ammo."
I'll have to second that one. I hand load, and seldom shoot factory ammo.
If it were me, A bottle of Crown will do. And would be complete overkill. You would have to sit down with me and have a few.
When a hunter helps you out, (I've been helped, needed help when there wasn't any, and helped others when I could). When a hunter helps you out, he's not looking for return. What he's doing is helping someone because someone helped him one time before. If I help someone, I'm not looking for return. I'd be quite happy if the person I helped, helped someone else someday.
But, if you feel you must, the gift card idea seems to be catching on. I read somewhere that nation wide, it is the number one requested gift at Christmas.
-Steve