Oooo...interesting question!
I think "traditional" and "contemporary" are broad enough that every style can be slotted into one or the other, but because they are so broad they are almost meaningless. For instance, if I described a quilt as a "William Morris" quilt it would mean a very specific look, with very specific colors, and even a certain technique (applique, I believe) in most cases. Yet that could be considered as "traditional" as any nine-patch in feedsack cotton!
When people ask me what kind of quilting I do I tend to describe the techniques and the colors I prefer to use, rather than a style. If pressed I might say "leaning toward contemporary", but even then I would feel the need to qualify that extensively.
I'll be curious to see what others say on this thread!
Alison