The problem with holiday traditions is that, though comforting and familiar, they can also be boring. That's why each holiday season, I search for ways to mix it up a little without breaking the tradition of turkey and all its trimmings. Stuffing is the perfect place for experimentation: the only constant is the bread, and even then there are lots of choices. Once you choose a bread, you still have dozens of options for other flavors, like nuts, sausage, olives, and all kinds of vegetables, herbs and spices. It's hard to go wrong as long as you choose flavors that are harmonious together.
The trick to making a good stuffing is getting the moisture right. In the end, the stuffing should be golden and slightly crisp on top and moist inside. You don't want it to be soggy or dry. Different types of bread will require different amounts of moisture to achieve this texture, so be sure to add the liquid gradually, evaluating as you go.
In my opinion, stuffing baked outside the bird (also called dressing) is the way to go: your turkey cooks faster and more evenly, your stuffing gets nice crisp edges, and you don't have to worry about undercooking. However, if your tradition insists on baking the stuffing inside the bird, just cut back on the liquid by a cup or so—the stuffing mixture should be moistened only enough to barely cling together, so that it can still absorb turkey juices. And when you stuff the turkey, leave enough room to fit your hand into the top of the cavity; this will ensure that the stuffing has space to expand when as it cooks.