I thought season five was great.
The whole Steve Bushemi (spelling) angle was great. The way that Tony had no alternative but to knock off his own cousin to keep the peace, the torment he faced, it was great.
Borrowing from the Godfather and Michael Corleone killing Fredo.
Look for Tony to be haunted by the ghost of his cousin in season 6.
I would guess that season 7 will wrap up with Tony finally getting busted by the feds and thrown in jail.
From there, as long as the franchise is making money, look for a movie or two.