The problem with using tables:

• mixes presentational data in with your content.
  • This makes the file sizes of your pages unnecessarily large, as users must download this presentational data for each page they visit.
  • Bandwidth ain't free.
• This makes redesigns of existing sites and content extremely labor intensive (and expensive).
• It also makes it extremely hard (and expensive) to maintain visual consistency throughout a site.
• Table-based pages are also much less accessible to users with disabilities and viewers using cell phones and PDAs to access the Web.