Hate to say it, but..."it depends".  

For me, a laptop.  I can dump the cards to the hard drive, and then
dump the hard drive to CD or DVD, perhaps multiple copies.  In
full-paranoia mode I'd carry one copy of the CDs and mail another one,
plus have the copy of the photos on the hard drive as yet another
backup.  And the laptop lets me get a GOOD look at the photos.  And
put up preliminary galleries, and keep in touch with my life.   And I
transfer a copy to my server at home over the network (overnight) if
the connectivity allows it.

But for other people, the size and weight of the laptop is a
deal-breaker, or the power requirements.  I wouldn't try to take a
laptop up Everest (and the hard drives aren't speced to work at that
altitude anyway).

I'm not happy with using the potted hard drives because it means my
pictures are in *just one place*.  Yes, I've lived with that with film
the previous thirty-some years, but it was always a worry and
something I went to consderable trouble to minimize the risks of.
With digital I can have my pictures in two places at once much earlier
in the workflow, so I do.   (One could use *two* potted hard drives.
Or there are devices like them but which burn DVDs, and you could burn
multiple copies.)

There are now a lot of different choices; check them out and find the
one that works for you -- or that works for *this particular
trip/project*.

i have a portable viewing device, 120 GB HDD in it.

www.vosonic.com

A supplementary to Mikael's question if you don't mind Mikael,......are
there any comparative reviews of the small cheaper store only (rather than
colour screen to view the pictureson) devices?
Thanks