I am a teacher using calc with pupils to create spredsheets and charts. 

The problem is that the automatic axis length is equal to the highest value in 
the spredsheet as you can see in the picture here:
http://www.thorandre.net/Mine_filer/oo_calc_chart.bmp

I'd say that the automatic length of axises should be a bit higher than the 
highest value so you can clearly see the top and botom values. Maybe something 
like 5-10 persent higher? (Of course it can be changed manually after, but it 
takes some time and means to many steps to remember for the most of us...) I 
would guess that adding some value to the axis max and min automatic by default 
would be possible..? -I am not the programing genius, but you guys certainly 
are!

As an "easy" way to solve the problem the x- and y-axis lenght could be added 
as a choice/page in the chart wizard perhaps.

thorandre