Don't know if it was already posted, but minimum install size during setup of Leopard was 6.x GiB I believe and SL is 8.x GB. Don't feel like hurting my head with math, but where is the 7 GB of space savings?
Oh yea, wasn't it some Apple dude with a heavy accent that said something about advanced compression that made the install size small? So does SL really install the same amount of drivers by default or was he trying to make things sound cool?