I never played Luigi's Mansion for some reason. After launch it seemed to disappear from the collective conscience of Nintendo gamers. Is it worth tracking down?
Luigi's Mansion is just lacking in perceived value. I rented it for a four day rental and 100%ed the game in two days. And I suck at games. I RENTED the game and felt ripped off because I could have paid less for a two or three day rental.
The actual game is pretty fun though. I enjoyed it, it's just that once I beat it there was nothing to do. And yet this is supposed to be the big Gamecube launch game. The game that competes with HALO. Nintendo is supposed to make this big comeback with the Cube and the game that gets the most promotion is this no-challenge must-rent. If Nintendo gave the promotional effort they gave this game to say Pikmin instead, maybe THAT would be a big Nintendo franchise. If they focused their promotional effort on Rogue Leader maybe that would have sold some Gamecubes. I could make a big list of why Nintendo inadvertingly sabotaged the Cube and Luigi's Mansion would be near the top of the list. It's really just the worse possible game they could have released at that time. It's not a horrible game but it's a perfect representation of just how clueless and out to lunch Nintendo was at the time.
Though if you like collecting games and can pick it up used for less than 10 bucks you'll probably enjoy it. It is fun, it just has no legs to it.
Regarding Sonic, I figure these days Sonic Team just throws darts at a collection of generic ideas when they decide to make a new game. This time "spooky Sonic" was picked. It isn't like Luigi's Mansion's concept is super creative or anything. The setting of a haunted house is cliche as all hell.