I dont really like Knoppix. Knoppix is freaking great to show your friends the world of Linux and experience their great LiveCD but in a stable every-day system, I'dnt reccomend it. With Ubuntu you get the same advantages as in Knoppix (LiveCD, APT etc) and its better supported and the community is great,
But how about Slackware?
Do you really belive windows BS? Try linux use something fresh not something old and refurbished!!