There's an excellent book called Eat, Pray, Love - I forget the author atm but it's a fantastic book. And I'm not recommending it just because it was on Oprah the other day, it thankfully didn't make it on her book club list. I read it over the summer, and gave a copy to each my mom, sister in law, and mother in law, and they all loved it. The book and a box of chocolates or something along those lines may be good.
People talk like gift-giving is so hard, but it really isn't. Think about what she's desired in the past, what she looks at longingly when you're out together. You put some thought into it. I know I've posted this before, but I'll say it again. The greatest gift I've given someone to date was when I was 16 years old at Christmas. I was deeply in love for the first time with a good friend and one day when he was over teaching me guitar, he noticed an Alf toothbrush holder I had on my shelf in my bedroom. He then told me of how when he was a child, he had an Alf doll that he treasured, but he decided to take it into the tub with him one day and it soured and his mom had to throw it away. He said it crushed his world and broke his heart, then we went back to playing. After he left, I set out to find an Alf plush. It wasn't hard, luckily Alf was "in style" that year, so I found a little stuffed Alf on a keyring. I gave it to him for his birthday/Christmas (he was born exactly 6 days before Christmas and I was poor, lol) and the look on his face and in his eyes was priceless. He kept it on his guitar case, since that was the biggest thing we had in common. Just think about what you know her heart really wants. If you've been with her awhile, you should be able to discover it before it's too late.
no one really knows better than you, there can be many things people could tell you to give her and she would like, but not really mean anything to her. Im thinking you know your girl, think of what she likes, what she does, and try to find something for that, even better if you make it yourself.