Wow, a lot of questions...1. What kind of PC and what hardware works best with Kolibri? And what kind of PC and hardware should I avoid?
Nothing in particular.2. Is it still not possible to connect to wireless LAN?
There is no support for wifi as of yet.3. Is there still only a text browser? Is there no really usable browser? And what about E-mail?
Unfortunately, yes. There is work on the way for an allround browser called netsurf. There is an e-mail client called Liza, but it doesnt work with encryption and is not included in the automatically built images.4. Is there only a simple text editor? No office program? Or at the very least something like Wordpad as opposed to just something like Notepad?
There is no word-like program. Tinypad kind of resembles notepad but has some enhanced (programming related) features.5. Is it possible to use printers? What kind of printers work best? What printers should I avoid?
In short, no. There is a driver for USB printers but no programs use it. HP printers seem easy to support.6. Is there any other kind of hardware that you would recommend or that I should avoid?
check this page: http://wiki.kolibrios.org/wiki/Hardware_Support7. Is there a command line?
Yes and no. There is a shell, but it's not really integrated into the OS.8. Are the file system, the structure and the commands more like in Windows and DOS or more like in Linux and Unix?
It doesnt really resemble any of them, but closest is probably unix.9. Does Kolibri only run programs specificly written for it, or are there some programs written for specific operating systems or written in a specific programming language that it will also run?
Any program you want to run on KolibriOS needs to be written specifically for it, or ported. 10. If number 9 is only possible by using emulators, what kind of emulator for what kind of OS works best?
There is a dosbox port, it's included in the CD-image AFAIK.11. If Kolibri can't do / does not work for most of these things, what other operating system is there that is most like Kolibri which CAN do most of those things?
Some lightweight linux distro probably, maybe puppy linux or damn small linux.
Hope this helps.