well i have to say that i tried few more linux dist and found this, i use at this moment ubuntu studio as i'm about music(you dont need it as you can install all goodies on your own) before i had debian (i like it but it's not really good for desktop i think) many time we saw RedHat as it's used most of the companies and again is very good, i like openSUSE as well, the main think is what you like and what you need.
When i need to repair win box i will go for live cd/dvd Knoppix as is very good if you install it on usb (as any linux dist)
so my advice is to use knoppix live and just study tree directory and so on it will be nice to start and remember knoppix is debian based dist and is quick and stuffed with nice sort of software for admin tasks.
My answer to what's good linux for hacking is this one : there is no good no bad dist, as after while working with linux you will find out that there are all same in my opinion.
one think tough FreeBSD is not linux dist i have to say so dont mix it with linux
freebsd is probably on of the best unix os on market and is opensource and even mac osx kernel darwin is based on freebsd kernel (i have mac as well and i love that machine as is well configured with hardware and easy to use, dont forget that i work with music and mac is one for this made hehheheeh)
Use virtualbox for linux to find out how hard or simple is for you to use it and you will find out witch one is good for you
my friend told me this "fuck linux man and get freebsd as this is real os for servers (guy have his own ISP company running only frebsd so i sad i will." hmmm it's not easy but PCBSD is good start i think.
As we can see there are many os's to go with...... freedom is that one when you know what you want and need and can actually make choice....
check CBT Nuggets on net and you can buy video school for linux
hope this will help
all the best in exploring opensource world