I suppose you could simply stop using instant messages altogether. I almost never use it anymore. Hmm...maybe I should update my sig., since I very rarely use it now, but I digress.
Try doing what I do: For people I meet in real life, I try to arrange face-to-face meetings whenever possible. The only other forms of communication I'll use with those people is the mail or phone calls. If I talk on the phone, I try to keep the conversation short, since I frankly don't enjoy talking on the phone for long periods of time. I also don't text message. Only pre-teen girls do that. I'm a man in my 20s, and no one, as far as I know, uses text messages regularly.
I have e-mail, but I don't like to use it for people I've actually met face-to-face. I primarily use it for notifications from web sites, or people who want to contact me from message boards like this one. I figure that a computer shouldn't be necessary to maintain contact with people in real life.
Ben