For me its a toss up between In absentia and FOABP, perhaps even a tie. In absentia has some really incredible songs and a nice variety.
There is no song I don't like on FOABP and anesthetize is legendary.
I definitely dig The incident, but have never been huge on Deadwing.
Ultimately, I miss Porcupine Tree. When I saw them for the first time on the Incident tour, never did it cross my mind that this would actually be their last tour