Actual Space on 64GB

My SSD shows up as having 55.45GB available. It's definitely on the low side considering a 60GB external drive I have shows up as 55.5GB available after a clean format. There's been some discussion on the low capacity here.

55 pre mac osx and around 38 gb left when you turn it on for the first time from apple. You can remove printer drives and extra languages you wont use and recover 4-5 extra GB.

Wow thats weird.. are 64GB SSDs actually 60 gigabytes marketed as 64 in reality? The reason I ask is because 80 gig drives show up as 74 gigs in real life, a difference of 6 gigs. So how could a difference of 9 gigs show up in a smaller capacity drive?