BW's endgame was great. Starts from Route 10 all the way to the end. Route 10 with Cheren and Bianca's uncertainty, the Victory Road buildup with the badges and music, the climb to the top, the Elite Four, then N and Ghetsis hijacking the whole thing, culminating in N summoning his legendary and your stone summoning yours. Fighting his with yours is really cool but you don't even have to use it.
I'm not terribly fond of most legendaries but I really like what they did in BW and to a lesser extent the Unova games by having them have context with regards to the characters rather than being just "oh it's this big thing that does shit". It just worked.
