Probably because I'm a writer and not a particularly eloquent speaker, I've come to prefer e-mail as my primary mode of communication (other than face-to-face, that is).
I've always had an uneasy relationship with phones. Although I carry a cell phone, I'd really rather not talk on it very much. I do have a bad habit of calling my sister to chat when I'm stuck in immovable rush hour traffic, but other than that I really only use the cell for quick calls that would have been e-mails if I'd been at my computer.
Our home phone might as well be out of service. It's there for the sole purpose of connecting our alarm system and TiVo to the outside world. I hear it ring sometimes and I presume that some people might leave messages on the answering machine, but I do not check them for weeks at a time. I think my husband might, but I'm not sure. As I see it, if you're my friend, you have my cell phone number. If you're calling me at home, you probably just want something from me.
I'm a little ambivalent about instant messaging as well. I like the new Google chat functionality and I'll use it now and then to talk to my husband. I'm also on Windows Messenger, but only a few of my friends and co-workers have it, so it's kind of a waste of desktop real estate. Anyone who wants to have a lengthy conversation with me that way at work would probably be better off just walking down the two flights of stairs and talking to me directly. Or calling (*shudder*).
My preference for e-mail over calling is usually okay, except when it comes to my band. The guys all have e-mail addresses, so I thought that would be our default communication medium. I'd send e-mails to the whole group between practices, hoping for input on the band website, photos, song lists, etc. Turns out, they don't check their e-mail very often at all. To me, that's crazy talk. I check all five (six?) of my e-mail accounts several times a day. It's the modern-day equivalent of waiting anxiously for the postal truck to arrive.
I asked them about it at our last practice and the consensus was, "If you want to talk to me, just give me a call."
My husband is encountering a similar communication style difference with his teenaged drum student. She prefers to set up practice times with him via text messaging rather than talking over the phone. I think it's safe to say that she's the only person to whom he ever sends text messages (except one to me once, to show me how it worked). I can tell it's having an influence on how he IMs and e-mails - he's suddenly using acronyms that I'm pretty sure he didn't before. Luckily, they're easy to figure out.
So, what communication technology do you prefer, and why?