That would be 1440x900

And then 1280x800

Both are 16:10 aspect ratio, so both should work just fine for you. You may notice that with lower resolutions everying might look a little less sharp, washed out etc. Every monitor handles it differently though; usually they can interpolate other resolutions just fine.

/edit: If you're unsure you can always do the math yourself (even for other aspect ratio): 16 divived by 10 is 1.6. 1680 divided by 1050 is also 1.6. Same goes for 1440 divided by 900 and 1280 divided by 800. ;)

BTW: Why would anyone laugh? 16:10 monitors where quite popular for a time and people wont throw them away just because full-HD 16:9 monitors are the declared standard right now. I use a 16:10 tft myself...and I play in 1680x1050 just fine. :)