Let me explain why I don't call myself an Instructional Designer - I do a lot more than design instruction! To me the word instructional brings forth notions of teacher led instruction in formal education settings. Chalk and Talk, Tell and Do, information being 'pushed' from the facilitator to the student.
OK, I know that this is not what the majority of today's Instructional Designers actually do (they could even be offended by my description). However the problem is that the title Instructional Designer feeds into the notion that learning happens in formal settings and that knowledge is something that can be transferred through instruction. I think that the title has seen it's day and that it's time for all 'Instructional Designers' to rebrand themselves - Learning Designers, because that is what you we do.
We design so that people can do what they need and/or want to do more effectively.