I would like to get hold of a reloading and ballistics software package to better manage my reloading and also to map out and understand the ballistics of my loads.

Can anyone recommend the best software for these purposes?

I find Point Blank to be really useful, for keeping up with loads and trajectories, etc.
It's free on the web.

http://www.eskimo.com/~jbm/ballistics/ballistics.html

it's simply the best, imho - I use it more than several of m buy wares.