I quite like SMS. I do reply with a "thanks" or whatever to birthday wishes, etc. aswell.
Quickness of a reply or anything doesn't bother me. If it's something important I'll call.
SMS is so much easier for me sometimes than calling, cause it's just a min(or less) to write the message and send... Where as if you were to call me then I most likely wouldn't be able to hear you as some little boy is usually whinging after the phone if I'm talking on it.

I don't always reply to messages either, so I don't often do one word replies. Never reply to joke messages either.