partition HD - amount to "shrink"

hello,

have vista 64 and want to create the partition for win7 64. search did not show a tutorial for this in forum under "partition" that I could find so using disk management in vista it shows:

596 GTB NTFS on HD

size before shrink 610477
size available to shrink 175241
and asks to enter an amount

so just to install win7 plus maybe some software what amount would that partition need to work well then? Did the partition thing on another computer with smaller HD and had no probs installing win7 32 bit.

thanks.

Msongs

I would go with 40GB partition for 7. (41000)

I just did what you are doing with my wife's computer.

If you run into a problem with the resizing of partions in vista- check this for the free partitioning software and instructions.
http://www.vistax64.com/software/204802-managing-partitions-dos-software-vista-x64.html