Jobs!
a gun rack?
Come on man you're married to this woman, surely you know what she likes?
I think a really beautiful necklace is a good idea. It is something that can last a long time and she can add to her collection of jewellery and always remember that it symbolizes your first four years of marriage together.
Seriously consider the gun rack dude...
Deodorant
It's cheesy but what about handmade coupons? This is stereotypical but maybe a nice tea set with unique teas and biscuits?