[Anima Templi]

Well pretty much everything has already been said. You should under all circumstances experience an increase in battery life when moving to Linux. This is due to Linux being much more lightweight than Windows will ever be. When looking for distro's it's very hard to find something your whole family will find simple enough and don't get scared of.

Crunchbang is one of my favorite distro's and it's definitely worth a shot, but it might be a bit difficult in the beginning. Debian is nice too, it's dead stable and you will most likely never encounter any problems with it. The only "problem" with Debian will be that it tends to be a little behind when it comes to updated software. This is due to the Debian developers weighting stability over new features. Some like, some don't. Anyway, go with Geoff's suggestion and pick one of the spinoff's of Ubuntu, they will look very similar to Ubuntu itself and it should be a breeze to use. If none of this works for you I guess you are left with the last option; Trial and error. Pick out some distributions and simply work your way through the list. Good luck!