In my time as a LCMC (Linux Certified Microsoft Converter) I have found that Knoppix is a great way to get started... I still use it on days when I need something to 'just work'.. that and SuSE 9.x are awesome..
SuSE is especially good for people coming from the MS world..
However 'apt' the package management system on Debian distros is just so so so so so good..
Welcome to the other side, I am sure you won't look back.