Install Debian, the stable branch of development will run fine on a p120, Debian only needs a minimum of 12MB of RAM and 110MB of disk space!
The BSD's need to run a lot of software under Linux emulation to get a decent desktop.
Use the enlightenment window manager, you can use enlightenment along with KDE. (just need to edit one config file for this)
Install konqueror, konqueror is lighter. It's also the base for OS X's new browser.
You can use Flash for linux with Konqueror with no problems, blackdown java works well too.
However, you will need to install WINE to run a windows version of QuickTime. Apple does not make a Linux version of it.
Once you got your system configured you can compile and patch a new kernel for yourself.
A 2.2.x series kernel is all you would need to a p120 system but in this case I would patch a 2.4.x kernel for good perfomance with the following:
Pre-emptive kernel patch -> Reduces the latency of the kernel.
Low Latency patch -> Use in combination with the above, they affect two different aspects of the kernel.
Compressed Caching -> compresses a cache in you RAM, increasing the size of available RAM.
The latest kernel that you can apply all of these patches too is 2.4.19. Trimming it down is another topic in itself, but it can be done.
Have fun!
Stef
