The 4400 had an original concept and wasn't your average cop/hospital/detective type of show that gets rolled out season after season with a new cast. This show delved into the ideas and fantasies we all have about becoming more than what we are. Having special abilities and powers is alluring and living vicariously through the 4400 and those who took promicin shots was pure fun. You could see the good, the bad and the ugly. Not every ability was a good one, some were disastrous. The shot had a 50% chance of killing you if you took it. And then there were the original 4400 and what they were trying to do, build, preserve and fight.
This was such a fun show and it got better every season. The fourth season brought things together and I could see it only improving and getting more deliciously complex. Too bad it was cancelled. That's the hallmark of a great show these days, though. Most people just want their House or ER or NYPD Blue/CSI's. The 4400 is remembered as truly enjoyable with bits of mystery, action, suspense, sci-fi and adventure all in one show.