My work manufactures a Slackware based network device, and I've had no trouble getting used to it. I don't think it's any harder than any other distro I've seen.
Kevan, I think that the best distro to hack with, is the distro that you feel most comfortable with and can install all the things you want on it with as little bother as possible.
If you're looking for a flexible Linux distro with a huge support base, then I'd recommend you go with something Debian based such as Knoppix or as funkybunch78 has mentioned Ubuntu.
CEH, CCSA NG/AI, NNCSS, MCP, MCSA 2003
There are 10 kinds of people, those that understand binary, and those that don't.