In my opinion,the two outstanding buys at the moment are the SATA3 640GB Samsung model HD640JJ and the Western Digital 640gb SATA 3 model WD 6400AAKS,as regards performance and cost per GB. There seems to be a price war going on by Samsung, to firmly establish its range. Consequently both of these are really cheap and offer outstanding performance.especially the Western Digital-all to do with areal platter density, each platter has a capacity of 320gb. Locally,the Samsung is available for about us$85-the WD for us$95. My choice is WDs for a RAID 0 array Interested what others are buying.