Also, if you design for 'the lowest common denominator', how does your site look when people view it in a 1920 x 1200 monitor?
Do you ever consider spoiling the experience for them?
Not being rude, but seriously curious.
For a real example: http://hicksdesign.co.uk/journal/ implemented a 4-column layout at the end of June that looks great on both my 1920 monitor, and my mobile. Try resizing your browser window to see the effect in action.
I would like to have a very fluid design for all resolutions, i.e. % based, but I am running into many problems.
In an attempt to just get it fixed and launched, I started this poll to get an idea as to what the popular resolutions are.