Since you've been together for a while, you probably know by now what there tastes are like. If you think they would enjoy getting another piece of jewelry, go for it! Given that you're saying the old necklace you got for them is now all faded, I assume he/she must really like it a lot and wear it all the time.

In my opinion, it really doesn't matter how expensive a gift is it's the thought that counts. If you are really struggling for ideas, how about just getting him/her a nice bouquet of flowers and taking him/her out to see there favorite movie? I'm sure they would love that.

Perfume/After shave would also be a nice thing to get for him/her. Also, you might want to get it because you guys did go out once and were probably friends, so it was a way of just saying that he/she was thinking about you. These are my guesses though so it may be for another reason.

You are the one who knows what they like. You've been around them long enough to know what kind of person he/she is and what there interests are, all you have to do is think about it.

What I would suggest is keeping a list of possible gift ideas. There is nothing wrong with that, it is actually something that I do myself. Every time you come up with a good idea, or every time he/she mentions something that they would like to have, write it down. Once his/her birthday or Christmas approaches, you can pull out your list and get them something off it. That way you'll never be stranded for a gift idea again, and you'll also get these priceless "how did you know I wanted that" every time.

How about getting him/her a beautiful bouquet of roses and taking him/her out for dinner at a fine restaurant? And perhaps a nice romantic walk after that? I'm sure they'll be pleased with that!

A piece of advice: if you do decide to go ahead with this plan, call the restaurant a few days in advance and make a reservation - if you just show up on the day itself, you might be out of luck.

Do you know something they would really want? You could give it to them and kind of relate it to your friendship. For example I know this guy who knew a boy/girl online and they said once that he/she needed a new CD case. So he/she got them this CD case and got him/her a pack of cards because they had met playing a euchre game. The person really loved it and thought it was so sweet. So it could be something simple like that or you could give them something like a stuffed animal.