I've been thinking about different methods and situations I use for conversations. I still really, really like instant messaging. It's convenient, and can be used in different ways. You can use it for real-time conversation, or it can be used in more of a "get back to me when you have a spare moment" type of conversation, and you can mix and match the two. You get presence information about the person you're talking to, so you have some idea if they're busy or otherwise can't talk to you.
I still hate the phone. When talking on the phone, that's the main thing I'm doing, as opposed to IM, where I can hold a couple conversations simultaneously while still doing something else that doesn't require much mental effort. The nice thing about the telephone is that you get to hear the other person's voice, so it's much more expressive.
Marc and I use voice chat when we fight our competitive WoW arena battles, and it works well there, because we need instantaneous communication. We've tried it elsewhere while just playing the "rest of the game" normally, and it's much more awkward. I'm pretty awkward on the phone, but in the game it's even worse. I don't have two-hour phone conversations, but I need something to fill the awkward silence when we're chatting while playing. I end up talking really slowly, or just trailing off into nothingness, or forgetting what I was saying in the first place. It's weird. It's given me a good idea of just how awful I am at phone conversations, though.
Conversations at dinner or around a board game work pretty well for me. I hear peoples' voices, and I get to see body language and facial expressions. Both of those activities have a primary focus that is not talking to the other people there, even though you may go out to eat or play games mostly to have an excuse to talk to people. My biggest problem here is that I'm not good at interrupting people (with perhaps one exception who may or may not read this), but I get pretty frustrated if I'm trying to say something and don't ever get an opening. IM is great too; you can interrupt the conversation whenever you want and talk about something completely different, and it doesn't seem weird or inappropriate.
I type very quickly, though. I'm sure that IM is much less convenient for people who don't. I probably just need to become better at talking to people I can't actually see. Without the context of being able to visually focus on peoples' faces, I seem to be unable to mentally focus on the conversation when I'm actually talking. This probably has something to do with the fact that I use like eight minutes of time on my cell phone each month. I'm just out of practice.