I take my laptop through airport security often. I have flash drives, SD memory cards, mobile phone SIM's in my bag. I've never had a problem with data loss on any media. If worried keep it in your trouser pocket - it may not even set off the alarm.
I've also had no problems with the x ray machines at airports but I would suggest that if the files are that vital you leave a backup at home and burn the files onto CD and take that with you as well. Just to be safe.
I think I'm right in saying that the hold baggage X ray is generally more powerful than the hand baggage X ray, so avoid hold baggage.
If it is a plastic framed one, it may well not set off the personal scanner, so I'd keep it in a pocket and "forget " it was there - that's what I do, & it normally doesn't set the airports' security off (has done so, though).
I agree with the policy of taking a backup on CD, & would advise against using a CD-RW. I've always suspected that they might well be affected by even low-level X rays.
Stuartli ~ Not sure about your view. X-rays are surely just a high energy part of the electromagnetic spectrum - they are light! The dye in the disc is sensiteve - for a cdrw, but not a cdr. The airport scanners that you walk through ARE magnetic, and work on the principle that something that deflects the magnetic field sets the alarm off. A small paperclip won't set one off, whilst the same paperclip unwound will set it off.
Film certainly IS fogged by airport x-rays, especially high asa/iso numbers (more so at primitive x-ray scanners in 3rd-World countries). On long haul flights high iso film can even be fogged whilst in the cabin! click here for details from Kodak