Here's a quick list of some common resolutions...
5:4
1280x1024
4:3 (not very common at all now but I think these two at least are important)
1024x768
1280x960
16:10
1280x800
1440x900
1680x1050
1920x1200
16:9
1366x768
1920x1080
Personally I would never use a ratio other than 4:3 because I hate stretching
Does anyone know who made luadump?