Great question, Sam, and lots of interesting responses. Many have experienced the cylical nature of collecting.
I just wanted to mention that in the early phases of collecting, or when moving to a new theme, there is usually a learning curve. It is during this period that you tend to accumulate watches. You learn from each acquisition and then move on to either complete a theme or move up in quality. This is best described as a refinement phase.
My short answer to your question, however, is that I would always take quality over quantity. But one does need at least a few watches in the watch box to do adhere to this!
Regards,
Andrew