grats42: Use the level of CSS that you need. You need to take into account your potential visitors/customers, the amount of time and effort you want to put in, etc.
As it is a business that might expect a range of visitors with a wide range of browsers you might want to keep a table in there to give you your columns and then use things like DIVs to divide things up in the columns (rather than adding new tables or cells). It is a very different audience to a site aimed at people who would be likely to update their browsers more often (web professionals, etc.).
On the time front - it will take you more time to develop a CSS-only solution and test it heavily across various browsers to make sure it looks as good as possible in the Big Three and degrades well in NS4.x (some designs can look pretty good in older browsers pos. due to a good combination of luck and hard work!!). You might not want to invest the time (which isn't a sign of laziness as anyone who has cried blood over some fiendish cross browser bug will tell you).
In the end it is your call. Use CSS to extract various elements (fonts, colours, alignments, etc.) from the page and use alternative HTML elements (like DIVs) where you can to trim down the number of tables used. If you want to take the next step and abandon the use of tables then you need to think it through. I know a lot of people who have taken the plunge are grateful they did (although it is easiest to make the move on personal sites or sites aimed at a more technologically able audience rather than a business) but it is your call. If you do (or if you don't, of course) we are always on call for a browser/platform test or a review if you aren't sure of anything.
Emps