What file system to use for data partition

[xcessi]

Hi..I am about to attempt dual boot with iDeneb v1.3 10.5.5 and Win XP SP3 on the same drive.
I would like to create a third partition to store data files. (JPGs, PSD, AI, etc)
What file system should the third partition be so that both operating systems can read /write this data.

Thanks