Debian, Fedora, or something else?

So I wanna jump into Linux, which free to download distro should I go with?

The first thing you'll need to know is that LINUX IS NOT WINDOWS.  You WILL have to basically relearn everything you know about operating systems (which probably isn't a lot anyway).  Most of the people that think Linux sucks just didn't give it a fair chance.  Note that you WILL be using the terminal.  It's not hard at all (after about an hour working with it), but if you've got religious objections to the CLI, don't even bother trying.

Now, I'm going to give you some advice, and if you're serious about getting into Linux, you'll follow it.

1)  Go to a bookstore and get a noob book about Linux.  One that teaches you some basic terminal commands and where to go for help.  It would be best if it's up to date and distro-specific.

2)  Get a noob distro.  Ubuntu/Kubuntu is good.  If you do go the Ubuntu route, there's a (supposedly) EXCELLENT book called Ubuntu for Non-Geeks.  Use this distro to get a feel for Linux.  Go through your book, try installing and configuring things, get intimate with the command line, compile your own kernel, etc.  Now, the noob distro is just a taste.  You'll probably run into a few walls caused by your own noobishness.  That's normal.  If, after two weeks you aren't scared off, move on to step 3.  Do not get comfy with this noob distro, or you'll never really learn anything.

3)  Linux From Scratch.  It's time to hand compile an entire Operating System.  Sound daunting?  It should.  LFS is a freely available guide, and all you have to do is follow it.  If this doesn't scare you off, nothing will.

4)  If you're still paying attention, move around and experiment with different distros.  Among the key distros to try are Gentoo, Debian, openSUSE, and Fedora.  Become familiar with their package managers, support forums, etc.

5)  Finally, find any distro you like.  I settled on Gentoo after trying about 30 distros.