I am planning to build a new computer and I wanted to get some advice on Raid5 and Raid 1+0.
I don't think anyone has asked this question of you yet ... but what are you wanting to use the storage for ?
Operating System ?
Personal documents and photos that are irreplaceable you can never afford to lose ?
Music/video/pron collection ?
Corporate filesystem ?
Database ?
Scratch disk for video editing work ?
Depending on what you want depends on the configuration of the underlying disk.