The three I mentioned are the ones I know are most newbie-friendly, although even that varies somewhat. I stayed away from other distros as I do not have all that much experience with them, however as they have been around for some time they must be doing SOMETHING right. For instance, I first started out in Linux using the Ret Hat OS, then some BSD -which landed Me a job in a Solaris shop, then switched over to Slackware and then Red Hat Linux on Sparc. All that within a three-year period.
Just play with a few. I am sure you will find something suitable within a short period of time. Just remember: NO INSTALLS! Play with the live CD first. Or live DVD...
Ummm... make that ‘Red Hat’, not ‘Ret Hat’, distro.