Alright, I see alot of misinformation here. For starters, creating a web page using a certain resolution, say 800x600 for example, makes that page render properly using that resolution only! When that same page is displayed on someone else's laptop, or home PC monitor, the page will be displayed using that screen's current resolution, NOT the resolution you used when designing the page. Don't create web pages for one specific resolution! There are too many different aspect ratios and screen resolutions to expect a "one size fits all" scenario, that with web design does not exist. Here's the solution: Use CSS3 Media Queries to create resolution adaptable code. Here's an example:
@media screen and (max-width: 800px) {
styles
}
@media screen and (max-width: 1024px) {
styles
}
@media screen and (max-width: 1280px) {
styles
}
See, what we just did was specify 3 sets of styles that render at different resolutions. In the case of our example, if a screen's resolution is larger than 800px, the CSS for 1024 will be executed instead. Likewise, if the screen displaying the content was 1224px, the 1280 would be executed since 1224 is larger than 1024. The site I'm working on now functions at all resolutions 800x600 to 1920x1080. Another thing to keep in mind is that not all monitors with the same resolution have the same size screens. You could put 15.4 laptops side by side, while both look the same, both could have drastically different resolutions, since not all pixels are the same size on different LCD screens. So, use media queries, and start creating your website with a laptop screen with high resolution, particularly 1280+. Also, create each media query using a different resolution on your laptop. You could use your resolution settings in Windows to adjust down 800x600 and creating a media query at that res, and then switch to 1024x768 and create another media query at that res. I could go on and on, but I think you guys should get the point.
UPDATE: Here's a link to using media queries that will help explain more, Innovative Web Design for Mobile Devices with Media Queries
That tutorial will show you how to design for all devices. There's also tutorials for Media Queries specifically. I developed the entire site to render on all devices, all screens, and all resolutions using no subdomains, and only CSS! I am still working on support for tablets and smart phones. The site renders perfectly on any laptop, or your 50inch LCD TV, and many pages work perfectly on all mobile devices. If you put all your code on page, then your pages will load lightening fast! Also, be sure to pay attention to discussion in that article about the CSS "background-size: cover;" or "contain" properties, they will make your background graphics fluid and able to render perfectly at all resolutions.
Follow the sites tutorials and you can make a single web page that renders on everything and anything!