How do you choose a project? What “calls” to you the most?
I guess it's kind of like obscenity--I know it when I see it. Unlike a lot of those who've answered the question so far, I don't like the ladies (Miribilia or Lavender and Lace). I will never stitch a "realistic" animal. No crouching tigers for me. Nor hidden dragons. I'm not really keen on the dragon/fantasy stuff, but I won't say never.
Since so much of the stitching I do is for other people, I do try to take their tastes into account. Of course, even if cousin Hildegarde really wants the most frou-frou of crap for a wedding present, I might tone it down a bit so that I can show my face in stitching circles.
I'm not put off by difficulty or fractional and specialty stitches. So I don't judge that way. There are colors I prefer, and I wish more designers would use brights in interesting ways. I'm very eclectic and my stitching tastes are too.