questionswhere's the best deal on a 3tb external hard…

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If you want 3 TB of space, you're going to have to go with multiple drives- the largest consumer hard drives available max out at 2 TB for a single drive. Getting two 1.5 TB drives is an option, but if you want the space for a single Time Machine backup, you may need a RAID 0 array (two or more drives acting as a single drive). In that case, your cheapest option may be to get a RAID 0 2-drive enclosure like this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817182192 (just an option, I haven't really been shopping for these)
and then two 1.5 TB drives. The Western Digital Caviar Green 1.5 TB drives are on sale both at NewEgg and at Amazon.com for about $90 each, and they seem to be very good drives.

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Of course, there is the new Seagate FreeAgent GoFlex 3TB Black External Hard Drive STAC3000100. It is ONLY available as an external drive so far. Newegg Item #: N82E16822148580