If we're talking about "the big one", let's not forget with all our electronics that wonderful feature of nuclear detonations: The electromagnetic pulse.
This is a fast way to turn your laptop, blackberry, cell phone, etc. into a paperweight. If you have data you want to keep, photos, etc., I recommend backing them up to CD (and having an install CD for your operating system, too, in case you're able to restore it at some point), but if we're talking TEOTWAWKI, that's probably the last concern we'll have.
Blessings,
B