You will need the first partition to be a FAT 16 Primary partition of between 1 and 2 Gig. FAT 16 so that all the rest can natively read and write to it because for the Microsoft Operating systems ALL will have system files and the boot loader installed there.

Since you don't mention what you are testing and what apps you might or might not install the rest boils down to deciding just how much hard drive you want committed to Linux and leaving it unpartitioned and using the rest as an extended partition.

In REALITY, with the number of Operating Systems you want you would be ahead to simplify your task and purchase System Commander.

A PROBABLY BETTER solution would be for you to check into either VMWare's Workstation or Microsoft's Virtual PC

Both allow you to install all the Operating systems as virtual machines within the Host OS (in your case Winsows XP Pro) making them all usable at the same time and able to share all your resources. Partitioning would be of little necessity as you can decide how much room you wish to allow the OS as you install it. This use of Virtual Machines also has the added benefit of avoiding constant rebooting to test in other Operating Systems as they run as applications within the Host system.