Er, shoot, it doesn't always work.
Here's the specific text of the error when I get the hang on suspend:
Note: The computer successfully suspends if I simply unplug the external drive, though this is a scary solution to have to resort to.
end_request: I/O error, dev sdb, sector 64
Buffer I/O error on device sdb1, logical block 1
I think the difference this time was that I had a program accessing the external drive.
As a sidenote, the specific text I changed in the script recommended by fugrank was:
for drive in $( /bin/ls /media/GANTRITHOR ); do
Perhaps I should have used "/dev/sdb" instead of the specific name of the drive I was dealing with ("GANTRITHOR")?
for drive in $( /bin/ls /dev/mmcblk?p* ); do
Any help would be great! Thanks!