What distributoin should I use if I think that RedHat, SuSE and Mandrake are too newbie for me but Slackware, Gentoo and Debian are too pro for me? I may be a newbie myself but I'm not afraid of using commandline.

You've kinda painted yourself into a corner. From there, you must
use one of the "lesser-knowns." If you're ready to give up the
darkside, then install Slackware-10.0 and learn Linux. If not, perhaps
a Live-CD such as Knoppix would get you moving right along.

currently (and my longest installed distro --very nice) is debian based (so you get access to all of the debian archives) but with an easier install (which debian.org is working on as well).
I'm using Mepis <www.mepis.org> and it is pretty sweet.

if adventurous, testing releases can be downloaded, or stable releases
it is based on debian sid (unstable) but quite stable. then you can apt-get update or apt-get install if you want.

very easy install.

can be used as a livecd (run it off the cd before installing) and has good hardware detection.

my $0.02 , but i've been handing out the livecd's because of my confidence in it.
once ready to install, you run the livecd, log in as root (password root) and go to the install icon.
it walks you through and then leaves you to muck around with gnu/linux debian.

hope this helps.
until debian gets their install easier, i'll probably stick with mepis (and maybe after too)

If you are not afraid of using cmd line;-)
Why don't you try Gentoo (http://www.gentoo.org )....

I have already tried Slackware and it was great but there weren't the software I reaaly need and I don't know how to configure things like mounting CD/DVD without using the root and to change permission to windows partitions. I changed to SuSE because it had the software but soon I realized that it wasn't good for me. I think I'm going to give Slackware another change.

Try gentoo...
I have tried several distro's like Mandrake, Suse, RedHat, Fedora but gentoo is a different flavor I think... Portage is incredible...
If I were you, I would give gentoo a chance...

why wait for your programs to compile everytime you want to use one?

with debian you get about 10,000 programs to choose from and no compile time... with mepis you get debian with an easy install, and your firewall etc already set up for you.

when you want to do an update to your programs (for security reasons) there is no wait for re-compile. when you do an entire upgrade to your system there is no wait for re-compile.

why is everyone waiting around so much when there is so much to do?

tongue deep, deep in cheek.

I have tried RedHat9, Fedora Core 1 and 2, Mandrake 9.2 and 10, SuSE 9.1, Gentoo (could never get it to work), Debian Woody and Sarge, and finally found the one I was looking for in SimplyMepis 2004.01. It just rocks! It gives you the best of everything. The stability and configurability of Debian with the ease of Mandrake. Very user friendly without disempowering the user. It's just awesome!

slackware is good - try it again. here's how to mount as non-root: http://www.losurs.org/docs/tips/sysadmin/user-mountable. i'm not quite sure what you mean with changing permission on windows partitions.

That's a good guide!

Edit: I originally posted an incorrect statement in response.
Thanks to cedar for catching my mistake...

oh, sorry about that. or an alternate is adding user to the group cdrom or whatever device it is that you want to mount.

Tried Slackware and it was good but there was I didn't know how to configure. I changed back to SuSE 9.1 Pro because it is easy to configure and this time I didn't have problems because I discovered some software I didn't notice earlier.

SuSE is sweet, stick with SuSE and try other distros in your spare time to learn Linux.

yes mepis is what your looking for

Check out Libranet, its another distro based on Debian.
http://www.libranet.com/