No sense in going sci-fi with this... Make sure that your tables are set for percentages rather than hard fixed sizes. When you view the pages in 800, it should be cramped, but not horizontally scrollable. When you view in 1280 it should expand accordingly, but not look too spacious.

One rule is to center your overall content to 800 (778 to be exact), then you don't have to worry about it at all... no matter what resolution someone is viewing from.

This is a great consideration you are making with resolution. The Reason: Some people are viewing from home on their huge screens, while others at work on their lunch break are viewing from the crappy 800's their bosses make them view from.

Keep in mind that 90% are using IE 6.0 or 7.0 .