Reducing Carbon
In response to the movie The Inconvenient Truth, it would seem that the most important action we can do is to consider how we can influence the amount of carbon dioxide released by our actions. Water use, battery disposal and CFCs are important but do not address the main issue raised in the movie.
Transport has already been addressed and represents the biggest source of emissions we create individually. Reconsidering recreational air travel is a toughie.
But one of the other things that we can do is get involved in tree planting or increasing the number of plants in our environments. The councils do some volunteer tree-planting (http://www.aucklandcity.govt.nz/whatson/outdoors/volunteer/treeplntng.asp) but it seems we missed the bus on it (it finished for this year in August). It might be something to get into later. I did tree planting on two occasions with the council - on that hill next to the motorway (near the South-Eastern Highway exit) and also on Waiheke. The speed at which the reforesting of such areas is restricted by the number of volunteers.
Another factor is to buy locally. All things from abroad have had carbon release to transport them the distance.
Any other ideas?