Amazon has the Seagate STCA4000100 4TB USB 3.0 Backup Plus Desktop External Hard Drive for $140 with free shipping. Goes for $176+ elsewhere. Features one-click custom backup and transfer speeds of up to up to 5 Gbit/sec.
A fairly thorough review of the 4 TB one, as Amazon mixes reviews for different capacity drives, is available here (provided that this site doesn't botch the link):
A fairly thorough review of the 4 TB one, as Amazon mixes reviews for different capacity drives, is available here (provided that this site doesn't botch the link):
http://www.amazon.com/review/RKBYJTS8IN9U1/ref=cm_srch_res_rtr_alt_7