I have the Acer 2216w. which I also have at 1680 x 1050 for normal wear and tear. What I did since I am not a PC guru, I found a 16:10 widescreen chart and paste it on my monitor, this way, if I need to lower the res, because of any game, I can always use the correct setting and avoid exactly what Stew2 just warned you about.
Here are some charts that may help you
16:10 - Wikipedia, the free encyclopedia Screen Size and Resolution Comparisons