I'd recommend you install Linux Mint 13 or 14, and no older than that. Linux Mint 13 is the current long term support release, with support till April 2017. Linux Mint 14 is the latest release with the newest software; support till April 2014. You can download either from kc1di's link.
If you are currently using the main edition of Linux Mint 10 (GNOME 2), you would probably enjoy either the Cinnamon or MATE editions. GNOME 2 has been discontinued, though MATE is the continuation of GNOME 2 under a new name. Cinnamon aspires to give you a somewhat similar experience (a task bar at the bottom of your screen with a list of active applications, and applications organized into categories in your menu) but using modern technologies. Cinnamon is developed by the Linux Mint project and is an exciting desktop environment