Which screen resolution is best?

For quite some time now I 've noticed most flash sites are designed for the 1024x768 screen resolution. Now, I also noticed most clients (at least here in Puerto Rico) don’t even realize the monitor resolution can be changed. They’re stuck with the 800x600 (I say it’s the res for the ignorant). I mostly design my sites for 1024x768, looking to achieve the smaller and cooler look. But when the client open their sites they don’t see the site as it is supposed to… and no matter how many times you warn them about the res setting, 90% won’t change it… Should I get stuck with the 800 res? Should I keep up with the 1024? Should I throw away a better viewing for lack of knowledge?

All your comments will be welcome.