Mandrake is the easiest, has the most bells + whistles, while RedHat tends to be more tested and less cutting edge (for corporations, etc).
You may try Knoppix, which is a live linux on cd. You boot and run right from the cd. Don't even need a HD in the system. Full GUI (Debian X-windows), wireless support, Open Office, etc. Good way to learn Linux without having to install it.