I'll move this thread to the Engine section, as it's better posted here than Starting with GameStudio.
The widescreen resolutions are 1280x720 and 1920x1080. But there are some laptops with some kind of an oddball-16:10 resolution...something like 1280x800 and 1920x1200.
I have two monitor resolutions supported via my Magnavox 30" HDTV: 1280x720 and 1368x768 which were added via PowerStrip:
http://www.entechtaiwan.net/util/ps.shtm My HDTV supports 1366x768 but because PowerStrip only allows me to add resolutions that are an additions of 8, like 1280, 1288, 1296, 1304, 1312, etc. but it's better not to support either those 1366x768 or 1368x768 or any kinds of odd resolutions for gaming...I'd suggest only 1280x720, 1280x800, and 1920x1080. But bear in mind that higher resolutions require more video memory, so lower resolutions, even 1280x720, can give you better performance than 1920x1080 or 2560x1600 (!!!).
Those who want to play games with a resolution that high enough for very sleek graphics like 2560x1600 (16:10 aspect ratio) will need to have a system with a Quad SLi graphics card from nVidia.