Innocent question : Are there people still using Debian?
I mean the answer is of course yes - a couple of diehards or people locked into some old application or two.
But I mean are there significant numbers of people still choosing it on its own merits?
Yes. Look at it from another perspective. Everyone using a Debian based distro is essentially using Debian in some modified form.
http://en.wikipedia.org/wiki/List_of_Linux_distributions#Debian-based