Or, you could use the options available to you through your profile. See below for steps to enable this.
Hover your cursor over "Profile" and then click "Forum Profile".

In your list of available links, to the left of your profile detail editing area, under "Modify Profile", click on "Look and Layout".

Click to enable the checkbox next to the text, "Show most recent posts at the top."

Click "Change profile" button at the bottom right of the page (directly underneath the list of options, mentioned above).

Should be it. After that, you should see the latest post, every time you click on any thread.