I noticed StackOverflow appears to be targeting screen resolution widths of 1024px or more. I also checked Amazon, NBC, MSN, & AOL which target more lay users, and they all appear to be targeting the same width.
Is 1024px the current recommended width for web apps targeting the largest cross-section of users who use default monitor resolution/browser size?
Use liquid layout. Then you can easily accommodate everyone from ~800 to ~1600 width, and with a bit more work and care even lower-resolution devices too. This also gives users @1024 some leeway to zoom the page if they find the text too small.
Remember there’ll be things like netbooks which don’t have the big screens we expect today. You can get away with a horizontal scrollbar, but if you have to scroll the page just to get the main body of text in, you’re lost.