let me explain

i am using virtual pc to set up a virtual network, i want to include on that network to "hacker" machines, one being windows xp and the other being a linux machine, i know many hackers use linux and many classes that teach security/ceh will use linux to hack/pen test the network
i'm just looking for reccomendations as to which distro if any, would be better for this purpose than others as i can't remember which distro the instructor used in a class i attended in which he cracked WEP
i know you can do these things with windows, but i want to understand the process from both sides
thanks