Well, I still use tkcon and tkdesk quite a bit, so I wouldn't comment on the popularity. I am a bit biased and generally don't use fancy graphical stuff. But I do follow the Tcl/Tk lists and newsgroups and there are quite a few people doing Tk stuff based on the discussion there.

* Okay, I just mentioned fancy graphical stuff and newsgroups. I feel old. I need a nap.