I suggest you read the U-boot thread (http://talk.maemo.org/showthread.php?t=81613) carefully. Take your time and ask questions (there, or here, as this is your thread anyway . Once you get the picture, I highly recommend that you install U-boot.

In general you only need one kernel. Kernel-power or CSSU-kernel (which are the same anyway) is sufficient (let's say it this way, stock kernel doesn't have any advantage over kernel-power, but kernel-power has many advantages over stock-kernel).

Even if you stick to one single kernel, it is very useful to have U-boot, especially if you tweak and mod here and there. The possibility of using the U-boot console to boot a specific kernel with very specific parameters has saved one of my N900s, which was unbootable and both SD card and USB didn't work!

Plus it will allow you to experiment with Nemo or any other alternative OS's without having to touch Maemo.

Τhank you for the tips guys!

Got it with the pipe symbol.

I installed the KP and the latest FCam drivers. I had some dependencies problems, probably because of the testing and extras-testing repositories. I disabled them for now and the KP is in use.
I also disabled the devel repository to be sure about the apps I'm installing.

Everything is good regarding the rootfs and the /home usage.
Indeed, some things got optified like you said.

I got the 720p video support working as well. That was a good one!

I will see what is going on with U-boot, seems really useful and I hope to get it right this time.

I am very interested in the keyboard and mouse support, because I work with many devices connected (laptop, TV, phone ... ) and I want to be able to use one keyboard and mouse to control them all. I haven't checked it out yet but those links are marked as favorites on my browser.

Thank you all again!