I’ve got some Macs these days, but I’m still a vi kind of guy. It’s what I do pretty much all my work in, as far as work that involves editing text goes. It had always driven me a little crazy, though, that when I was using vi in iTerm (which is an excellent terminal emulator for Mac OS X - I highly recommend it), if I copied text from elsewhere and pasted it in, if you pasted in a line that went over the width of the terminal, it would break the long line up into many little lines and generally never worked right. This is, not surprisingly, a big headache.
The fix is stupidly obvious. Change the term (you can do it in Bookmarks -> Manage Profiles, then click on Terminal Profiles) from ‘linux’ to most anything else, like xterm, xterm-color, xterm-256color (which seems to be much the same as xterm-color, to be honest), and it will work right. I wish that I’d figured this out a little sooner though, like nearly four years ago when I got my MacBook.