Marshall - 4:48 pm on Jan 23, 2012 (gmt 0)
If you use HTML 5, there is no declaration, just <html>
Regardless, if it is just the tables, not cells, causing the problem, I would just reset the table margins:
margin: 0 auto;
margin: 0 Xpx;
Some margins are affected by doctype just as different browsers do, however the latter is usually most notable in body padding.