My opinions
Debian
I consider this one of the best distributions out there if not not the best
for anyone looking to get up and going. You can make packages from source as
with most all distributions and or you can simply install the package. I used
to be an extreme hacker, far more than Gentoo/Crux people, thanks to the
the lack of packages available for Slackware (and I say that as a thank you
Patrick). But sometimes, you just want to get stuff working. This is where
Debian shines. However, this is also poor choice for learning.
Slackware
Yeah, it may seem like I bad mouthed it, but by God, for a system that isn't
specifically compiled for a given architecture, it's insanely fast. The
developer actually listens to you. If you think I'm kidding, send an e-mail
off to support for Slackware. Most likely you will get a response back from
Patrick Volkerding. This distribution is also very friendly and easy to work
with. You will probably end up learning more about Linux with Slackware than
any other distro out there. It was also the 1st distribution made and uses
.tar.gz (a common archive format across the land -- really). Although it's
called something.tgz, it's just a gzip'd tarball. Another note, I would just
use the simple one CD install, the other CDs had all the other packages, but
I didn't know that and I didn't have the bandwidth for it, so I learned :-)
Sometimes ignorance can be your teacher.
Redhat or Redhat based distros
This distro sucks, but is very rich in tools. This is where Redhat shines,
however as far as customizations go, expect Redhat to not care for you.. too
much. It can do it, it just requires more coaxing of the O/S as a whole.
Crux
This distribution is awesome as it is very close in nature to the BSDs. The
BSDs have a "ports" system wherein most of the software you require is
given to you as a Makefile. The Makefile tells it where to get the source
code from and what is required before the given port can proceed with
installation.
Gentoo
Based off of BSD ports as well but goes a step further. Not for people who
want to learn Linux. This distro although very useful for seasoned vets is
not a good idea for beginners. It's up there with Crux but has more userland
utilities for managing ports. This makes it easier than Crux however it has
a lot more possibilities for resident tweaks. It keeps track of USE flags for
ports. Imagine you want to use a port scanner called nmap but do not want
the GUI version. You can do that, when an nmap upgrade comes along, you will
not have to tell Gentoo that you don't want the GUI. You would set this option
as a USE flag.
Ubuntu
Based off of Debian. This distribution is for people who really just want to
get up and running and don't care for much else. Extremely user-friendly and
built to get you up and running in no time flat. As with Debian, you can
get really technical with this but you will probably never have to.
Final note
When you learn enough, you will realize that there isn't anything you can't
do to a given Linux distribution. It will always be at your mercy. This is
just meant to help you pick a distro based on who you are. I prefer Debian
and Crux. I may use Gentoo one day. However my parents are Ubuntu people.
So for beginners who like to tweak and twiddle with computers and options, go
Slackware. For beginners who just want to use Linux, go Ubuntu. For seasoned
users, choose between Crux or Gentoo.
Note: Gentoo people may argue, I can tweak and twiddle to my hearts content,
go emerge and portage! Well, that's exactly why Slackware will teach you more.
There is no emerge, there is no portage, there is a..
$ curl URL > filename.tar.gz
$ tar -xzf filename.tar.gz
$ cd filename
$ ./configure --help
$ ./configure --prefix=/opt --with-x-libs --disable-gtk
$ make
$ make install
and you have to remember what the hell you did or use ldd and hope it gives you
enough insight :-)