For those who don't know how to count pixels, please use the attached sizing guide:

If your monitor is a non-standard size, then please select the closest width (first number). I've allowed three options per user, as I'm guessing most people access the internet from a couple of locations (ie home/school/work, etc). If they're all the same size, or you only use one computer, feel free to only select one option

PS. Please feel free to boast/complain about the size of your VDU as you see fit...