Yes, I was specifically talking about copying things to and from vim, with/without tmux. Maybe its not a huge issue to all, but I always forget when I set things up on a linux machine vs. Mac OSX
gvim on mac/linux/windows will use the + register for the system clipboard. I'm pretty sure that a terminal vim with gui support compiled in will do the same (I know it does on Linux/X but haven't tested on mac or windows in a while).
This is true, but often terminal vims don't have clipboard support. For example the vim that is bundled with Ubuntu does not. This can be especially confusing for people new to vim, or sometimes you jump onto a random machine and find that "+y does not work.
I guess that's another thing to add to my list of "reasons Ubuntu is terrible" it's a minor complaint, but good to know.
[edit]
FWIW, "gvim -v" will probably give you clipboard support in a terminal on ubuntu, and ubuntu might have an "alternatives" tool to make the "vim" in your path have X support. "The Ubuntu packager compiled vim with the feature I want disabled" is a poor argument against vim; it would be like someone saying "I switched away from vim because I wanted to write plugins in Python" just because the packaged version of vim they use has python integration disabled.