I have two BCD996Ts and they are great scanners. The state of IL is currently migrating to a huge statewide APCO 25 digital trunking system called STARCOM 21. As the future progresses you will continue to see more and more systems migrate to digital modes, but one caveat before you get too excited.
Digital technology is on the rise in the communications world, but the public safety agencies are increasingly eying digitally encrypted systems as the encryption technology become cheaper and more efficient. There are plenty of operations (even the feds) that are running digital as we write here, but not as many are currently encrypted. The scanning hobby may likely be nearly nonexistent in many areas of the country as far as public safety communications are concerned in the next ten to twenty years.
Here is the problem for scannists as far an encryption is concerned. Unlike bands above 500 MHz and trunked systems were viewed twenty years ago, it is highly unlikely that you will ever see a scanner that can monitor encrypted systems.
All technical jargon and discussions aside, unless you are a system user (i.e. LEO), it is illegal to own or possess any equipment that can monitor encrypted systems. There will never be a scanner that can decode encrypted signals unless the law is changed and it's even illegal to own or possess a radio capable of operating on these systems unless you have permission from said agency. More and more public safety agencies are eying digital systems because they can outperform many analog systems on the market. Encryption is viewed as a means to ensure officer safety and protect what they believe are vital communications from falling into the wrong hands. Whether or not many departments are switching to digitally encrypted systems solely to get away from scanner listerns is a matter of debate.
With all of this being said, the 996 is a great scanner that has many advanced features. However, I expect this scanner and many of its brethren to slowly become useless over the next several decades as more and more communications systems migrate to the "unmonitorable" classification.
With the exception of major metropolitan areas and some state agencies, there are not many rural areas (prime chasing territory) that currently use APCO 25. However, this is likely to change, albeit slowly and painstakingly at best.
For more information, see the following threads at RR:
http://www.radioreference.com/forums/showthread.php?t=71368
http://www.radioreference.com/forums/showthread.php?t=71187
http://www.radioreference.com/forums/showthread.php?t=71714