Many years ago, when I was still in my 20s, the managing partner of my first venture firm, Milt Pappas, told me that he felt there were three terms that really mattered in a venture deal (other than price of course). They are:

1) The liquidation preference

2) The right to participate pro-rata in future rounds

3) The right to a board seat

From Fred Wilson. Taking the time to go through my Pocket these days, bunch of good stuff like this