I have been using a width of 750 pixels the last couple of months. I don't like to use percentages, because it can make the page look strange, with more complicated pages. What I would like to know is: 1.Which resolution is used most frequently - does anyone know the percentages? 2.What resolution do you design for and why?
In general I tend to keep the width around 900-1000px wide. I rarely use percentages, I like to work pixel by pixel I've said it before, and I'll say it again : These days, you can probably safely let go of keeping it under 800. Just think about who will be viewing your site. Will it be gaming nerds with huge monitors, or someone on a crappy PC in a public library...
I have mine from 900 to 980. On a 1024x786 resolution (old 15 or even 17" monitor), I've found that 980 is the most I can go before a horizontal scroll bar appears. But now a days, so many people have widescreen monitors ranging from 19" to one guy I know that has a 30" monitor. I agree with Kerosene, the site has to be tailored to your audience. If it is a corporate or business website, probably in the 800 to 980 range. If it is for gamers, or geared towards high tech people, you can go wider because most of that audience will have a bigger or widescreen monitor.