In what may be a sign of things to come, a report was released yesterday which states that Lords of Shadow the next Castlevania game from Konami will ship on 2 discs for the Xbox 360 while the PS3 version will only have one.
Regarding the necessity of going to two discs, Dave Cox, head of Mercurey Steam, said it wasn't the length of the cutscenes that were a problem, as "[the game's] longest one is 14 minutes, which is the end sequence." Instead, variety was to blame as "The game's around 24 hours long and every level's different. We have so much variety and we re-use very little assets."
The Xbox 360 DVD has much less space than Sony's Blu-Ray discs, and as games get larger and larger this problem will likely rear its head more and more in the coming years. Hopefully that trend won't begin to affect the price of games as well.
Luckily Lords of Shadow looked and played awesome at E3 this year, so two discs won't be terribly onerous to deal with. Castlevania: Lords of Shadow will release this October for the Xbox 360 and PS3