Cube Hardware Upgrade Options for Video Editing.

[RICARDO]

I am looking to upgrade my Cube to make video editing on iMovie3 and Final
Cut Express more efficient and productive.  Does anyone have any thoughts as
to which hardware component should be the better target for my upgrade
bucks: Hard Drive, Video Card or CPU Card?  I cannot afford to upgrade all
three, and if I can get away with upgrading just one of these I'd be a happy
camper, but if I need to upgrade two of them I may be able to stretch my
wallet if necessary.  But which component to upgrade, that is the question.

Appreciate any feedback.

RICARDO,
Alexandria, VA.