I have two 750gb WB Blacks in my Desktop and they run no warmer than anything else.
Also reading the power consumption specs they don't use materially more current than the Blue or green drives.
Frankly the only REAL difference with the Green drives is the color of the label
They have identical performance to the Blue drives.
In normal day to day use the Blacks don't seem that much faster, but normal everyday isn't
why I chose them,
First off I got them on sale at newegg and so they were the same price
as slower drives,
Second when those drives get really used is when I'm copying or moving a
large ammount of data all at once (often 60-100gb) and doing that those drives really shine
as the sustained read write rates make a difference....
But I discovered just the other day when another drive (one of my last Seagate 500gb drives) announced through my Win7 os that it was in danger of imminent failure, normally this wouldn't be a serious issue, but the drive was my media playback drive... so I cleared the files off one of my 750 Blacks (by moving it to the other 750gb drive)
and copied my playback library to the newly empty one from my backups
and discovered that I should've switched from the 7200rpm Seagate drive to one of my WD blacks this time last year...
It is noticeably faster switching between files and directories.
Looking up the specs my seagate by it's original specs has several times the latency and seek time of the WD750
And I've only got the 3.0Gb/sec drives
Generlly when looking for drives I decide what I can accept then wait as long as possible before buying it.
(Generally waiting for a Sale at Newegg:)
But "sales" on drives larger than 1.5TB are few and far between...