I send her flowers, but not necessarily on a special occasion. I send them at random times and sometimes to her work place. Of course, there is none. My wife likes carnations because they last longer than roses. On occasion, I will order her roses from Jackson and Perkins because they'll send her a live, miniature rose plant in a special container.
Clothing is always fun.
Most guys automatically think lingerie, but my wife doesn't really like negligees, so don't assume yours does. The same is true for church dresses. I'll surprise her sometimes with a dress. I have to accept the fact that she may not like something that I bought and she may not wear it more than once - if at all, but the payoff is worth the risks because when someone compliments her on a dress, she's quick to point out that I bought it for her. Silk pajamas with a matching silk robe are another great gift.