This question is asked alot yet I can't seem to find any good examples in search...(weird)
If you have never seen Linux:
1 Try Knoppix.. It's a "Live" Cd it will run from your cd drive. No install to hard drive.(if you don't want to that is.)
If are new to Linux and want an experience similar to WIN
1. Suse
2. Mandrake
3. Linspire
4. Xandros
I have not installed all of these, but most are on the easier side to install and get working.
If you are proficient with computers and are not afraid to do a little reading:
1. Fedora Core 4 (good installer, free version of Red Hat, great tools, a lot of reference material,etc..)
2. Slackware ( my favorite distro. I have tried a lot of distros, but this is the one I am most loyal to.( I always come back to Slack)
*installer is not the most user friendly but it is solid as a rock.
3.Debian - Everyone at the LUG I go to uses it. I've never tried it. They are kinda cultish about it.
4. Arch - Very solid L33t linux distro.
From your list.
RedHat- you have to pay for. A good business(enterprise) distro.
Mandrake- A good newb distro. The free version seems to nag you to get the pay version.(my opinion.)
Slackware- Again my favorite. Very solid distro. Most people have a love/hate feeling toward it. A good learning distro.
Vector similar to Slack, but better on older hardware.
Check out Linux.org and go to distributions tab. You can look through a bunch there.
Distrowatch.com will give you an idea of the distros and their popularity.
as stated above look at RUTE:
RUTE
My progression through distros has been:
Knoppix-->Suse 9.0--> Slackware--> Fedora-->Ubuntu-->Gentoo
I have tried many more but these are the ones I actuall "used".
I hope this helps.
Blair