Like others, I have given framed aerial photographs, but that gift is only good once for each land owner. Most of the ranchers and farmers where I hunt are annually given baskets full of freshly baked goodies; cookies, various breads, fudges, and venison, elk, or bison, salami and hunter sticks. Often, in the basket is a gift certificate to a nice stake house or other type of restaurant they, especially the wife, likes. I once had a farmer who really, really, really, liked his Jim Bean, so several of bottles mysteriously appeared in his barn each year the week before Christmas (you might want to be careful with the alcohol if his wife doesn’t approve of drinking). You said that he once hunted with you in your home state, invite him on another hunt. I hunted a ranch for a couple of years before discovering the owner, a native bowhunting Montanan, had never been in or hunted, any of the wilderness areas in Montana. The next fall I took my brothers and my horses and guided him on a three day (he wouldn’t leave his ranch any longer than that) wilderness bowhunt for elk and mule deer. He actually converted to shooting a longbow from a compound after that trip and is still a close friend even though the ranch sold several years back. Not quite as nice as Barry’s Lobster (thanks for the idea Barry), but a couple of times we have given landowners fresh salmon from Alaska. Like Mark, a couple of them have received a selfbow built by me. Each land owner I know has different things they like; what these things are best learned through personal relationships developed throughout the year, not just during hunting season. Not knowing your landowner it is hard to determine a personal gift, which is the type gift I have found they appreciate the most. Like you, I am continually looking for thing they might like throughout the entire year.
All said and done, most land owners I know are satisfied to know you respect their land, their lifestyle, and their family, anything beyond that is like icing on the cake, deeply appreciated but not always mandatory.