Best partitioning scheme for my HDD? Please advise.

[n j]

> What would be the best sizes for the
> disk partitions so that I don't run out of space on any of them while also
> leaving the maximum amount of space possible for the future software to be
> installed?

While I'd certainly go with a single partition as a solution for your
setup, if you really insisted on having separate partitions, you could
use a logical volume manager like Vinum which should, if I'm not
mistaken, allow you to resize partitions on the fly, reducing the
unused partitions and increasing the greedy ones.

-- 
Nino