Art that symbolizes something...
...like a famous painting
There are a lot of famous paintings in the world that portray human emotions. While you can't gift most of them to someone, there are a few that you can. Obviously, you will have to get a version made from a good painter, but it's worth the effort. Some famous paintings that depict a human emotion are Narcissus by Caravaggio that depicts self-love/obsession and Sunflowers by Van Gogh that depicts happiness. A painting like the Kiss by Gustav Klimt will be a great anniversary gift.
...like a rare photograph
There are a lot of photographs in the world that have gained recognition beyond what we can imagine today. Though getting the original print is an impossible task, you can certainly get it printed again. Most of the photographs portray negative emotions. However, a few like 'Lunch atop a Skyscraper' or 'The Frozen Niagara Falls' can be good choices. You can also get a collage of these done.
Things that money can't buy...
...like a homemade wine
With a lot of money, you can buy a lot of things. However, as the cliché goes, there are some things money can't buy. Similarly, you need to gift him something that is special, and not necessarily expensive. One such thing is making wine yourself. You can make wine at home, and make it just how he likes it. If you package it well, it certainly makes for a classy gift.
Something that is unique...
...like an old coin
There are certain things that can be valued high, not by their price, but by their availability in the world. Sometimes, a well-planned gift idea can work wonders. Unique artifacts are great collectibles. One of these, is a coin, that has stood the test of time. You can find these in selected stores, or you can also hunt down collectors and buy it from them.
Something that you thought a lot about...
...like a personalized puzzle
The idea is to present him a jigsaw puzzle, but not just any jigsaw puzzle - 'His' personal jigsaw puzzle! Get a special jigsaw puzzle of his face made. You can even make one yourself, provided you are a good artist! Before gifting him this unique gift, do try to solve it yourself a couple of times, just so you're sure that it's perfect.
...like a watch you styled
If he has all the money, trust me, being a guy, he also has all the famous watches. A watch is the most basic accessory all men wear. However, the chances of him having a custom-made watch is really low. Make one for him, just how he likes it. Don't forget to get his name inscribed on it.
Use these gift ideas, and come up with something really unique, something which he will remember, forever! Best of Luck!