Whether Gold is 'worth it' depends on i) how much it costs, ii) how much you're planning to fly next year, and iii) what routes, times and fare classes.

Say you're planning to fly 50K miles next year. Then Gold will earn you an extra 25K banked miles in 2006. That probably pretty much offsets the monetary cost of the MR you'll need to get there. So the question is, will you get any other benefits? If you fly mostly international, or hub-to-hub, or on very difficult upgrades like EWR-SFO/LAX, then you probably won't get any more upgrades. Also, if you fly routes like IAH-ELP or many routes into CLE where Silvers get upgraded most of the time, you also won't get too many more upgrades. And finally, if you fly paid first or full-fare Y, again you won't get many more upgrades. If you don't fall in any of these categories, there might be some extra benefit to Gold. But really the number of expected extra upgrades from being Gold as opposed to Silver is not that much.

In summary, I think the jumps from no status to Silver (elite access, elite seating) and from Gold to Platinum (Skyteam lounges, many more upgrades, exit rows) are worth much more than the Silver to Gold jump. (This despite being Gold myself.)

Of course, if you're really looking for an excuse to do a MR which you'd enjoy anyway, then just go for it! Flying CO is fun!