Try doing this:
1. connect all 3 to the RAID card (HPT card, right?). Make sure those 2 60gb Maxtors are connected as Master on each channel (this is if you're going to install the OS on the stripe set) and 120gb as slave. (make sure all 3 are recognized)
2. get into HPT bios (I think it's CTL+H... need to double check). Set those 2 Maxtors as a stripe set and name it. do nothing for the 120gb.
3. install XP (make sure you have the HPT drivers on floppy and press F6 during XP installation. Load up the drivers when asked during installation). XP installation should see 2 volumes during installation (your stripe set (120gb) and the 120gb single volume)
4. after the installation, you should see 2 drives in My Computer. If you don't, right click on My Computer --> Manage --> Disk Management. You may need to set up the volume in order to use it.
Go with NTFS... don't play around with FAT32... Hope this helps.