I just finished reading Dan Brown's Digital Fortress. As a techy it wasn't too bad: the processors were way faster than is technically possible, that amount of parallel processors probably wouldn't have been hugely more efficient than half the number (add processors = add communication overhead = reduce the efficiency boost of adding a processor) and one of the firewalls was a little suspect (X11 is the graphical user interface for Linux/Unix, so I don't know why they had a firewall level for it). Other than that, though, it was a great book that just used a little creative license.
One thing I did notice, though, is that the NSA are a little slow. As soon as they got the code for the pass-key at the end and put it into the Ceaser's Square I knew what the answer was. Well, not 'knew', because I didn't know the exact numbers, but I knew where the answer was coming from and what it was likely to be.
Maybe they should hire me at the NSA just in case they hit the same problem again