Nooo you can't end with Eclipse - then there's no Renesmee or Bella being a vampire or any of the lovely lovely things in that book!
The first book of Breaking Dawn can be summed up pretty quickly - wedding, sexy times, pregnant. That's good though, because there's SOOOO much in the rest of the book.
That being said, Breaking Dawn will be problematic too. They'll probably try to smoosh as many scenes were the wolves are "talking" to each other into scenes were they are all in human form - but they've probably addressed the "wolves talk to each other in their heads" thing before we get to Breaking Dawn anyway. The hardest thing is going to be Renesmee. Going to have to find a pretty awesome 4ish year old for that.
Back to New Moon though - dear God, I hope that they get the rights to "Ride" by the Vines for whatever montage scene they make between Bella and Jacob riding bikes. Because, lets face it, who hears anything else in their head when they think of that?