Knoppix is such a useful disc in and of itself; backup/restore tool (for Linux and Windows), Linux introduction and learning tool, Debian installer, and more--and free. It's the installer aspect that I'm so pleased with right now.
I recently reinstalled Linux to my system using the latest version, using the latest version of the install script. From start to finish, it took less than 30 minutes. After I answered a few questions, the rest continued unattended; the resulting install needed very little fine-tuning.
This was much better than my previous Knoppix install, from a June version. Though I was pleased with the eventual outcome, it took a lot more tweaking to get it to a useable state. Admittedly, I know a lot more about Linux now than I did then--and I hardly use Windows anymore--but the new installer script works great. I would dump Windows completely, if I didn't have to help the oldsters with it (I teach computers to senior citizens for a nearby city's recreation center) and answer questions for others (not that I mind--I'm here, ain't I?).
As much as anything, I did a scratch reinstall as a learning tool. I'm glad I did. Another good thing: using Knoppix, I was able to back up my old version in less than 15 minutes--I can always fall back if I have to.
In my opinion, with hard drives being so cheap these days, there's no reason for a serious/power user to not have a dual-boot (or even triple-boot) machine.