Most new motherboards come with sata raid as standard now, but if you are looking for a controller I recommend LSI...
http://www.lsilogic.com/products/meg...ta_300_8x.html
This one is the ultimate, but is probably overkill for what you want todo and it costs a bomb
http://www.lsilogic.com/products/meg...ata_150_4.html
This is a nice 4 port version that has raid and will do you fine for 4 drives.
LSI make very good cards, solid drivers and fairly easy to setup once you have a play with the menu options.
Other than LSI you have Adaptec, Promise or Atto.
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