I accidentally pulled my external enclosure off my desk thanks to the incredibly long 1 foot USB cable. Now my WD 200 GB Caviar drive beeps twice at me, waits 5 seconds, then beeps twice again, and just keeps going. I assume this is a bad thing, but does anyone know what it means? It ran perfectly until this happened.
Thanks.
Your drive may have a seized spindle motor, or a stiction fault. Stiction occurs when the heads land on a smooth section of the platters instead of their normal landing zone.
See http://en.wikipedia.org/wiki/Stiction#Hard_disk_drives
Stiction forces can often be overcome with gentle “percussive maintenance”. 
This thread may interest you (it has a couple of success stories):
http://forum.hddguru.com/samsung-portable-500gb-dead-t14351.html#p99445
See the warnings on page 5 of the following article.
Disk Drive Science (Steve Legg):
http://eprints.soton.ac.uk/7803/5/DiskDriveScience_copy.pdf
Here are photos of what can happen:
http://forum.hddguru.com/viewtopic.php?f=1&t=15911#p105001