What do you want the 3x500GB for? If you're thinking about putting OS+app on a RAID5 array, don't even think about. Even on my server-class hardware RAID card I don't do it. RAID5 is for storage only, any speed gained is just a bonus.
If you were to put them in RAID0, besides ~60GB being used up by the OS+app, are you going to put your data onto the remaining space??? I could see the excess being used as temp. storage e.g. scratch space for editing HD footages, but besides that, not much use.
Or you could grab another 500GB to make it 4x500GB RAID10. Then you can put both OS+app and data onto it with both speed and reliability.