I would have to disagree that FFX wasn't good, storyline wise. I found it amazing, especially since I really don't like FF type games as the game play of constant never ending grinding bores me to death. I simply played through the drudgery purely for the story. Anyways, thats a bit too off topic probably.
I would say the Underworld series, with Kate "freaking hot" Beckinsale, was conceptually amazing, but the plot was weak. In the first movie Vampires were just Human's wielding guns and leather. That was flat-out pathetic and a disgrace to the Vampire lore. However, I stuck with it and despite its glaring flaws, I can still watch and enjoy it because of its core concept/idea and its dark world. I do look forward to Underworld 3 (yes, I don't count the prequel, as its a prequel and not the storyline progressing forward as 1 and Evolution were, as should be the next one).
As for video games, I have a few. Old ones, though, so many of you might not know of them. Star Trek Armada II was interesting but basically a waste. You either played the Borg, didn't go up against them as AI opponents or got murdered by them if you did (although the campaign mode was fine). The Borg could create this ultimate ship called Cube Fusion, with normal cubes or Tactical Borg cubes (which were powerful enough). You combined eight of either kind and proceeded to utterly obliterate the enemy without need to shed a single drop of sweat worrying about losing the ship. Entire fleets could not take on a single Cube Fusion. I managed to get two at one point, and basically sat back doing nothing but telling them to move across the map, letting them kill at their discretion. It was horrible (in a fun, sadistic, mad cackling, but ultimately broken and soon to be boring way).
The next two were highly anticipated but failures. Master of Orion II and Master of Orion III. The first one, Master of Orion, is a seriously old school MS-DOS game, was superbly amazing and the re-playability was basically infinite. Number two was a joke of a game. If your race did not possess the Creative talent, it was nearly insurmountable to beat another enemy; let alone the almighty Antarans who randomly appeared and obliterated everything in their path. If you were creative, then the game was decent. The only race that had the Creative talent, aside from just customizing a new race, was the Psilons. Everyone else just ate solar radiation and died.
Master of Orion III looked so amazing and probably had a ton of improvements, but it was so micro-managed that I couldn't figure out half of what I was doing even with the manual helping me. The aliens were also a pain, being quicker and more powerful usually, and the bloody win conditions always ruined my plans for a prolonged war of attrition. You had a time limit to either rule over the council, defeat the Antarans, or kill all opponents. Good luck completing either while you struggled to get even one fleet operating. I was immensely disappointed over that failure of a game.