External disk drives and portability

I'm planning to use external disk drives for backup. I'm looking at
the nicely packaged enclosures from Maxtor, Western Digital, and Seagate.

I keep one set of backups "offsite," and this is giving me a bit of a
worry. Roughly once a month, I hand-carry backup media from my PC to
the "offsite" location. On the return trip, I hand-carry some media
from the "offsite" locaton back to my PC.

I don't know how wise it is to carry around 3.5 inch disk drives all
the time. These drives are designed for desktop use, after all.

Would it be wiser to use 2.5 inch drives? These are more expensive,
but these are designed for use in notebook computers. Perhaps they are
better able to handle the rigors of transportation?

Thanks for any suggestions. Recommendations for specific products would
also be gratefully accepted.

--
David Arnstein
--
Spammers: thank you for training my filters. You are all doing a
wonderful job. Keep up the good work!