One good distro is Kali Linux, from the creators of BackTrack (BackTrack is no longer supported). Kali is Debian-based (unlike its predecessor, which was Ubuntu-based), and it has tools for reverse engineering, data collection and analysis, HDD analysis, forensics, and many other purposes. I can't name the tools off the top of my head; you'd have to boot into it to know the full set of tools (if you've used BackTrack, it's a similar toolset, but simplified based on certain specifications).
Kali Linux is meant to be booted as a live disk (the docs cover how to do that), but you can also install it as a VM (which is what I've done). Persistence can be set up (see the documentation). Additionally, you can actually install it as an operating system, but I'd recommend against it.
One further thing about Kali is that you can customize it for your purposes (minimal install, certain types of install, etc.). I'm not going to go into detail about it. The docs contain further information, as does the main website itself (there is some information about the distro found on the site that isn't necessarily in the docs).
Kali Linux has an irc channel #kali-linux on irc.freenode.net. Be sure to read the docs before asking questions.