If it has to end, then they went out on a high note!
I mean wow people, I've had to sit through some rushed series finales in my time (See 'Sports Night'), but that one was well done. I don't feel the need to go every every bullet point, although props for a surprising Lou Diamond Phillips return! Too bad they never got Will Patton back. There was closure, new beginnings, and the episode didn't end on a huge note. it was a typical 'Numb3rs' ending with the brothers and Alan sitting in the living room, playfully bickering. Charlie's comment about everything staying the same was perfect.
Also did anyone notice that when they played the opening statistics about Don's gun at the episode start, the music was The Talking Heads song 'Once in a Lifetime'? That was the original opening credit music!
http://www.youtube.com/watch?v=N9U68u3ujlM
If they do get picked up for season 7 by some miracle, plan to call it quits at the end.
EDIT: Nicolas Falacci, the co-creator of the program, made his directorial debut on the episode! Didn't even notice until seeing the imdb listing!