I agree with Charley about not getting a "set". Knives are a very personal thing and requires some
research, knowing how the person uses knives and for what. The size of ones hand versus the size of the knife is important too. Can you take your niece to a good kitchen shop and let her try some of the knives. The shop should have samples that you can actually cut with. I like to cut on a tomato, because they are hard to cut unless you have a really sharp knife. I invested in Wusthoff a long time ago, the Classic series and found that they do not hold an edge very well. The Wunder knife listed above has great reviews on Amazon, however.
Start with a good paring knife, chef's knife and bread knife with serrated blades. From there she can move on to a few others. I think a good boning/slicing knife is important too. Also, she should feel free to have knives from different brand names.
You might want to consider a nice knife block for her too, one which fits in a drawer or if she prefers, sits on the counter top, if she has lots of room.