The 25 year mark is getting to be quite rare in this day and age, so that's really reason enough to celebrate. The official theme for this year is silver. That's more like it, right? Cause there's sooo much you can do with this theme. Apart from the obvious choice of jewelry, the other gifts that you can present include silverware, engraved silver key chains or a ƈ and 5' days vacation at an exotic location (second honeymoon, why not).
Not all of us put in the time and effort when buying a gift, where those who actually do, are the best of the lot. It shows you care and love this person enough to put that much energy behind something that sounds simple, yet isn't.