A learner's distro would be Mandrake, Suse or Fedora because Red Hat has gone enterprise. For Linux games check out http://www.tuxgames.com.
Your hardware is probably supported... if not you can learn to recompile the kernel for it. Linux can be placed anywhere on your HDD - it doesn't need to be on a primary partition on the first HDD. Choose ext3 or reiserfs for its filesystem. Linux can read NTFS OK and read/write to FAT well.