I ride a Trek 7200. My first handlebar change was changing the stem and putting on trekking bars. You need a quill stem because of the threaded Fork. If you google "quill stem" lots of cheap options come up. The trekking handlebars are nice, because they give you multiple hand positions and work with the original shifters and brakes.
When my suspension fork reached the end of its life I switched it for a threadless fork, and kept the trekking bars.