I would also recommend gift cards, preferably from a local shop but if you aren't local there are many wonderful on-line shops as well. I'm sure we can give you some recommendations on those if you want!
There are always a few things that I'd like to get but cost is keeping me back, but I truly have everything I need for what I do. And while some people truly do everything, I think most of us have a comfort zone or a point of view and so while one person may rave about something, another person (like me!) would have absolutely no use for it even if it is the best thing since sliced bread.
I know my non-sewing friends and relatives think I "sew" but really I only quilt any more and that is more accurately described as machine sewn piece work. I don't do hand work or applique or garment construction or a bunch of other things like embroidery any more either.
I think the greatest thing you can do is share your appreciation and interest in what she does. A lot of hobbyists (no matter what you do) are not well understood by the people they love especially since they get to see the failures as well as the successes. I've been trying to get my son and DiL to give me some ideas for more than a year now on what to do for the quilt I'd like to make in honor of their wedding (wedding was in June). Sure, I can make up my own mind about what to do for them (and I already have the wedding themed fabric I'd like to use for the back), but I'd really like a little input on colors or design or something to make sure it's something they like as well.