Preferred Communication Method At Work

I worked with people who prefer to communicate (work related stuff) via chats. I never really got that as they literally sat right next to me. The preferred method of communication apparently depends, but personally:

1. When it's something important, containing multiple points, or needs to be articulated, I usually put it in an email.
2. When it's not as complex or I want to actually discuss with a colleague, I would generally speak to that person directly.
3. If I can't leave my desk and the person sits far, I would resort to chats. But generally if I could speak to the person personally, I would do that and not chats.
4. If someone is not there, and it's something I want to make sure he sees, I'd probably leave a little note on his desk.

So what do you think are some of the etiquette when it comes to communicating with coworkers? Another question is on the notes, as a friend of mine thinks it's rude.