I'd send it all in too. Just make sure it is very well organized - for example, put all the phone bills in order, all the emails in order, all letters in order, and everything labelled and numbered with a table of contents at the beginning. This way all the proof is there. If the officer doesn't want to read it all, he or she will still see it's there, and if it is well-organized he can skip some. For emails, if there are a huge number, just print out maybe one per month over the course of your relationship, and then get a screen shot of the in-box showing the dates and subjects of all the others.
Somebody at the CIC help line also advised me not to submit all my phone bills, saying a representative sample was enough, but - I have read many cases from the Immigration Appeal Board, and sometimes one of their reasons for rejecting an application will be "they only have one phone bill from year x" or "they've only shown us a couple of phone bills from the early years of their relationship, so obviously they weren't really in love." In other words, if you ony send in a few phone bills, like they recommend, they might then accuse you of not having phoned much.