My MBP and iPod have been all over the globe with me. SFO -> KEF -> CDG -> LHR -> OAK -> LAS over the course of 3 weeks and it handled itself like a beauty. A word of advice however; Apple products are like magnets for theft, even in airports and even on the plane. Going through security will be simple, fast, and secure compared to the greater threat of someone walking off with it.
Back up before you go anyway. Keeping the laptop accessible from your carry on baggage makes everything go quicker. Keep your eyes on your stuff at all times, and NEVER pack it in checked luggage.
Coincidentally, the only data I've lost through a X-Ray scanner were photos still on a compact flash card. It could have very well been the card freaking out as they sometimes do, but it did go through 2 or 3 scanners and about half the photos were garbage.