I ask here i wanted new disk but what is better? External WESTERN DIGITAL My Book Essential 3.0 1000GB, USB2.0, 16MB cache, 7200ot, WDBAAF0010HBK-EESN or internal WESTERN DIGITAL Caviar Black 1000GB, SATA II, 32MB cache, 7200ot, PMR, 8.9ms, WD1001FALS