Hello folks.  I'm happy to report that I fixed my problem.
The problem was that the timeout in
/usr/src/sys/dev/ata/ata.c:ata_get_params() was set to 1 second for ATA
devices, which was too slow for my drive.  I increased this to 4 seconds,
which worked great.  I wonder if we could increase this timeout value for
the general source tree?  One second seems rather short, especially for an
operation which is not going to be time critical.  Four seconds might be a
bit long, but should work for the slowest of devices, and shouldn't be a
problem for faster devices.
	I wonder if changing the 1 second to 4 seconds could be done in the
development tree, and pulled up for the 1.6 branch before it is released?
If so, I'd suggest it, in case there are other laptop users upgrading their
hard drives, which appear to be a bit slow on the identify command.
-Brian