No Windows yet
I still haven't installed the other OS, yet. Not that I haven't tried, but for some reason my computer refuses to boot the XP disk. It works fine with Linux boot disks though. I don't know what the problem is. Anyway there just a very few thing I really need Windows for. One is my scanner the others are some games I like to play. But there is hope…
My scanner is a Canon 3200F which I bought without thinking about linux support 
. I worked with a Canon USB scanner on Linux before and so I thought they are generally supported. Well I thought wrong. However I just recently saw that there is someone actively working on a SANE backend for this scanner. Nothing really usable yet, but he seems to make prgress 
For the gaming part: My favourite game is running on Linux for years.
A few days ago a friend pointed me to OpenTTD – an much extended version of Transport Tycoon Deluxe which runs on Linux (and a bunch of other Platforms as well). You need some files from the old DOS game for graphics and sound. If you don't have the game yet, just get a cheap copy on eBay.
Maybe I can get Ankh running in Wine then I don't need to install Windows at all…