I usually change mine to "Sent from my mobile" or "Sent from (xxx) xxx-xxxx"
I keep a line like this for two reasons, one of which is proofreading related, but the more important is to let them know that the reason for my terse reply is not because I don't care or I'm upset, it's because I'm in transit (or just away from my desk).
I wish I could upvote this more. I'm off to change mine to the phone # one now.
I like it. Then if they're abrupt, I know it's to avoid typing not anger.
I agree. I keep it on because I worry that the auto-correct is going to substitute a really unfortunate word for what I intend and I won't catch it when proofreading.