I read Andromeda Strain by Micheal Crichton a while ago and the book was absolutely beautiful. It was completely a science fiction novel. It spoke about a virus from space. It has a broad target audience of science fiction lovers and I recommend it to lovers if the science function genre, one could also learn a thing or two as the author did his research well.
William R. Forstchen's - One Second After - Trilogy is a great modern day dystopian read. It is what today's world could be if some discharged an Electromagnic Pulse (EMP) over the US and knocked out all technology. The first book takes place from the first few seconds after the EMP goes off and how the world copes with the change, from banding with others, to struggling to find food/water/medication/ to roaming bands of gangs taking advantage of people struggling to survive. It does take on a very eerie tone of how realistic this future could be as this occurs in modern day America. Absolutely recommend this novel. Very well written.