A beautiful flower bouquet in combination with a basket full of chocolates and dry fruits. Since you are buying for your wife an anniversary gift, rather not think about gifting any kitchen item. If she is a bit romantic type of woman, she will get disenchanted with such gift.
Few gifting ideas for a lady in you life:
Flowers and chocolates
Flower bouquet with cute teddies will go for your girlfriend if you are into your puppy love stage
a heart shaped photo frame or pendant
a surprise vacation
if your wife or girlfriend is a passionate reader, gift her a novel or a book she would love
Though expensive gifts are good way to make her super happy, do also consider her choices and do not just buy it because it is expensive.
Women rarely judge the gifts by its cost. Gift something that will show value of your emotions and understanding for her.
While you send gift, do not forget to insert a lovely greeting card with few loving words. Do add some cute romantic wishes and wedding anniversary messages to show your love. It will work like magical butter effect with your gifts.