A few things i would get for a community collection / compile myself, they might be obvious, but obvious things sometimes get overlooked:
1. comprehensive guide to homeopathy / natural remedies
2. food preservation
3. a guide to making basic weapons
4. animal husbandry
5. a guide to home-made disinfectants, etc
6. solar energy guide - how to set up (providing the reader has or can get access to solar panels) and store electricity for an special projects (like
welding or something)
7. comprehensive guide to first aid
8. a book with stories of survival and beating the odds (for morale)
9. a guide to essential vitamins, minerals, and what wild foods (or cultivated foods if you're able to obtain or grow them) to find them in. (the
last thing you want is to survive the initial craziness and then die from scurvy

)
10. books from the 1800's - 1900's about life, science and technology. We have things easy these days, everything easily bought, but to see how
people did things then would be helpful, such as homemade farm equipment, food preparation, etc.
11. water-wise gardening. There will possibly be little to no running water and you want to conserve as much as possible. The last thing you want is
to be sacrificing litres of valuable drinking water on plants (if growing your own crops) when there are more efficient ways to go about it.
edited to add:
I would also probably look at printing hard copies of as many of these as possible before SHTF because we may not have electricity to view these on a
computer. The worst thing would be knowing you had these resources and not being able to access them.
[edit on 6-10-2009 by SerialLurker]