I have a desktop PC at work that shows a bad block.  PC runs Scientific LInux 5.0 and is a 2 TB  WD Green Technology 2 Tb HD (Caviar Green WD20000CSRTL).   This one has worked fine out of the box for several months.  No problems.  

Yesterday, the SMART diagnostics program smartctl (version 5.36) showed a bad block.  Deciding to waste some time on it, I used
http://smartmontools.sourceforge.net/badblockhowto.html approach.

So, I unmounted, figured out the block and that it had a file associated with it, determined the ext3 file system inode.  But, I could not deduce the file as it could not read the next file inode.   I zeroed out the position using dd and then rerunning smartctl that it showed another bad block:

# 3  Extended offline    Completed: read failure       90%      2151         3764125871
# 4  Short offline       Completed without error       00%      2151         -
# 5  Short offline       Completed without error       00%      2150         -
# 6  Short offline       Completed: read failure       90%      2146         3764125865
# 7  Extended offline    Completed without error       00%      2097 
 
The LBA is in the one partition on the HD
Disk /dev/sdb: 2000.3 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63  3907024064  1953512001   83  Linux

Since, it's a new HD and not expecting catastrophic failure, I did not run ddrescue.  Having a copy of spinrite around, I ran that  and the HD came out squeaky clean.  I use spinrite occasionally on windows xp and linux HD where I expect only one bad block.  Never had problems with it.   Spinrite did not find any more  bad blocks.  Of course, I had zeroed out the original one.  Rebooting and running e2fsck, the file system is clean.

Running smartctl again, I again  find a bad block at LBA  3764125871
# 1  Extended offline    Completed: read failure       90%      2169         3764125871
# 2  Short offline       Completed without error       00%      2169         -
...
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       0
  3 Spin_Up_Time            0x0027   100   253   021    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       6
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   100   253   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   098   098   000    Old_age   Always       -       2169
 10 Spin_Retry_Count        0x0032   100   253   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       5
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       3
193 Load_Cycle_Count        0x0032   195   195   000    Old_age   Always       -       15614
194 Temperature_Celsius     0x0022   115   111   000    Old_age   Always       -       37
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       1
198 Offline_Uncorrectable   0x0030   200   200   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   200   200   000    Old_age   Offline      -       0

Now, there are reported issues with WD Green Technology drives (parking the heads) and lag time issues with smartctl, although I can't find the web link where I saw this several months ago.  

I'm a bit confused.  I've never had an issue like this that didn't clear up (descrepency between smartctl and spinrite for instance).   Could it be the green technology drive not playing properly with smartactl (people report this)?   Should I run a bad block check with e2fsck?

A nondestructive test would 
e2fsck -ccv /dev/sdb

Advice?
Bill Lutter