Most ideal size for your Web Site?

It’s one of the oldest questions in the book: what browser size should I design my website for? Do I cater to people running lower resolutions such as 800×600, do I think my visitors want a wider layout like 1024×768, or do I think my visitors surf on a movie screen? Well, they probably aren’t going to be surfing on a movie screen, and chances are that they’re running something higher than 800×600. How about I stop with these generalizations and give you some useful info? How about a pretty chart?