How big would you think is the best to build a website. What resolution I mean. So it fits on the screen of most people, but isn't too small for users with larger screens?
I usually dodge that question by designing liquid layouts that expand to fit ANY size screen. The only time I constrain the width is if there's too little content on the page to fill anything wider than 1024 comfortably - in which case I design fluid, give it a min-width of 600 and a max-width of 1024 (give or take, I also use the IE expressions in the css to emulate max/min-width) Generally I consider fixed width designs a TOTAL /FAIL/ at intarweb... but then I've been running 1600x1200 for over a decade, multiple displays for close to two decades, and 'large fonts' since the 8514 was introduced. There's a reason I call fixed width designs "Crappy little stripes"
I think the general rule of thumb is to have the site fit on a 600 X 800 resolution but if you have ever looked at you website stats (at least mine are this way) only about 5% of visitors have that low of a resolution. Most are 1024 X 768 and higher. I think it is time to up the default to 1024 X 768.
I know I am still very inexperienced in this area and still learning web design, but I find from a layman's point of view, a well designed 800 x 600 site is much preferable to a liquid layout. I find all too often when the content expands to fit a wider screen, either the elements just spread apart adding lots of white space, and lose their visual appeal, or the lines of text become too long to comfortably read. As a result, I much prefer a fixed width website, maybe with some interesting background color or image filling in the spaces on either side.
do a test run on the site. Put a site up for a week or 2, check what screen resolution most people are using to view it. A gaming site or something your more likely to have people view in higher resolutions. My site (below) most people view in 800x600
Everyone keep in mind that cell phones and pda's are going to start out with smaller resolutions, if those people are likely to view your site (one of my former co-workers always checked Wikipedia with his Nokia). In Europe and especially in Asia, the use of cell phones to view teh InterTubes is much more popular than in the States/Canada. So, expect the usual-- that North America sometime in the future will catch up to the rest of the world : ) So be prepared for it if you want customers/readers to check out your site on their phone in the future and see something. What WebMachine said makes sense but goes with what deathshadow said-- fixed width is for sites where there isn't enough content to fill up larger screens. I find myself using fixed with more often than liquid (I don't care if viewers get a little scrollbar), but it really depends on the site.
Because Firefux still resizes content like a Mosiac's epileptic crack addict cousin? Because most people use fixed images instead of taking the time to understand or code dynamic headers? Because your art fag 'designers' work entirely in pixels inside PSD's and consider even thinking about not having 100% pixel perfect to their shit drawing to be enough to try and burn a coder at the stake... and no matter how many times you explain to them that with the range of screen sizes running from 640x480 and the number of displays out there ranging in size from 4" to 40" therin designing for a fixed size in a wysiwyg is outright retarded - they get their panties in a bunch, go 'uh-uh' and go on to churn out the same crappy little stripe bloated pile of crap pages over and over. Then come here trying to figure out why it doesn't work in ____ browser, doesn't index right on the search engines, wonder why four coders have just up and quit on them, only to have posters like Dan Schulz and I tell them to throw the entire thing out and start over.
I think 1024 x 768 is best unless you've got a particular reason to do a different size. Later, you can analyse the traffic that you get to see the resolution they're using and adjust the site to suit
760 is the recommended size, since people with 1024x768 don't always use have the browser taking up 100% of the screen space, and 760 is very friendly with 800x600 .. you have to take into account scrollbars if any, and the browser's borders itself. I think the majority of designs/psds are intended by the designer to be fixed-width/fixed-size which I'm trying to stray from, but fixed width designs are so "accepted" and so standard that it's hard not to make it fixed. If you can make it fluid/elastic, go for it. But if its fixed width I suggest not more than 760 pixels.