ubuntu 7.10 - dual-boot xp, partitioning problems

Alright, i'm trying to dual-boot linux and xp (xp installed first). Now, i've searched google for 7.10 partitioning help, but its all guides on previous versions.

I'm using GNOME partition editor to get the partitions for install:
"Minimum Size 26958MiB Maxmimum Size 76317MiB
Free space preceding (MiB): 0
New Size (MiB): 76309MiB
Free space following (MiB): 8
Cancel"


1.) Now i can edit the size, but how much should i change it to?
2.) After I change that, what do i do with this /root, /home, and /swap that i hear about?
3.) Or do i just choose "Guided use largest continuous free space" after i change the GNOME "Free space"?


------------------------
Here's what my installation "Prepare Partitions" section looks like
"
Guided use entire disk
IDE1 80GB (where my XP is installed)
SCSI3 74GB (games)
SCSI4 250 (files)



Guided use largest continuous free space



Manual"



now, which do i choose? i went to manual and it looks like:



"
/dev/hda
/dev/hda1 80015MB 28300
free space 8MB
/dev/sda
/dev/sda1 74348MB 20700
/dev/sdb
/dev/sdb1 250057MB Unknown"


Thanks in advance, let me know ASAP. take care (i'm so excited its working under safe mode!) -James