Bah, Gentoo blows for newbs. Sure check it out if you like it and the install directions are ok, then use it.
But in my experiance if you want to actually LEARN it your going to be screwing things up, and won't know how to fix it. WHat newb wants to spend 8 hours to install a distro and then 30 minutes to destroy it?!? Although going thru the install stuff gives some good basic information. IF you have a very fast computer, then Gentoo just may be the ticket.
THe best LEARNING distro is SLackware (IMO). It's simple to set up, has everything you NEED and not hardly anything you don't. IF you can handle installing Windows using dos commands like format and fdisk, within a couple weeks you'll be doing fine with Slackware. Plus you can download ISO's which can be used to create familar CD install disks.
Think of Slackware as the no-frills distro of linux.
Plus 90% of what you learn to do in Slackware is is directly applicable to any other distro ever made.
I'd say Debian is OK for a first timer. Although it's apt-get system is integrated in everything you do. The menus kernal compiling etc etc. Lots of what you do is pretty debian-specific stuff. Otherwise it's also a very handy OS.
Go with Slackware for the first time, then move on to others like Gentoo or especially Debian, then maybe on to the RPM-based Distros and see how they try to set everything up all automated and such.
HOWEVER!!!!
If you just want to USE Linux and avoid as much head-ache's as possible go with one of the newb-freindly rpm-based distro's: Redhat/SuSE/Mandrake. I have no personal experiance with Mandrake, but Redhat is good if you have a fast computer, and SuSe is nice. Personally I like SuSE more. That way you can get on the internet/do irc/e-mail play games or whatever you like to do.
THat way you can get a more gracefull transition from windows to linux. Going SLackware/Debian/Gentoo will be something of a culture shock.
But, learning linux is like learning a foreign language. If you just read about it, go to school (boot up in it) every once and a while you can learn to speak and read it. However in order to get fluent and understand normal-everyday talk easily then the easiest way is to actually visit the place were they speak it. Like going to Germany to learn to Speak German.
SO if you get frustrated with one distro, go try something else. With a fast cdrom and internet connect It would be easy to go thru and install/uninstall Redhat, SuSE, Slackware, Debian, Mandrake and a few others in a one weekend until you find something you like.(of course once you find one you like and it's a non-profit, then it would be nice to give them a small donation as thanks for all the bandwith you just burned up.)
Of course, if you have a second HD laying around I'd use that for experimenting. Just pull the Windows one, and keep it safe (or just unplug it). THat way their would be no worries about frying your MBR or something like that.
For a modern Distro I'd make at least a 4gig partition (Slackware "install everything" option will take 2-3gigs of space) partition minimally up to about 10gigs, and give yourself 500M swap partition. If you have more then 6-10 gigs to spare for linux, I would give yourself a couple gig /home partition to save downloads and documentation on so you don't have to lose your pics and mp3s every time you reinstall(just be carefull not format it.)
Have fun and good luck.
