only latest node has teaser, rest has title

how do i make it such that
only the latest node/story/event posted has the full title+teaser? and when that story/node becomes the second last i want it to show up only with the title. (which means all the other stories on the front page also show up only with the title too)

its been bugging me for a bit and i still dont know how to do this.

pls. help

thanks