Current pricing (CDN$) from a shop near to us here:
$120 Western Digital Caviar Green (WD20EARS) 2000GB (2TB) SATA 3 Gb/s 64MB (OEM)
$200 Western Digital Caviar Black (WD2001FASS) 2000GB (2TB) SATAII 7200RPM 64MB Cache (OEM)

They no longer even list the older 32MB-cache Green drives.
There are some smaller 1TB drives in stock with 32MB caches, though:

$65 Western Digital Caviar Green (WD10EARS) 1000GB (1TB) SATA 3 Gb/s 64MB (OEM)
$73 Western Digital Caviar Blue (WD10EALS) 1000GB (1TB) SATAII 7200RPM 32MB (OEM)
$90 Western Digital Caviar Black (WD1001FALS) 1000GB (1TB) SATAII 7200RPM 32MB Cache (OEM)
$100 Western Digital Caviar Black (WD1002FAEX) 1000GB (1TB) SATA3 7200RPM 64MB Cache (OEM)