Yeah, at this point, I'd definitely get a scanner that can do Project 25 Phase II. The new Unidens (BCD436HP and BCD536HP) should be out in January, if you don't want to pay a lot for a GRE PSR-800.
I believe all the TDMA talkgroups on the system now are encrypted, but as the system gets more users (DCFD, etc.), there will almost certainly be unencrypted TDMA talkgroups that you'll want to monitor.
Dave