I'm pretty sure I was low on HD space, like from 10 to 20 GB now there's around 50 free... I know Snow Leopard takes up less space, but i thought it was only like 7 GBs. Did everything not transfer from my TM backup?
There's also the difference in how the space is calculated. It'll give you larger numbers for free, used and capacity. (1KB = 1000 bytes, instead of 1024 bytes)