Duplicate content

My site has hundreds of pages with similar content - should I be worried?

[themoff]

I am worried that my site is potentially going to get penalised by the search engines, because I have lots of pages that are a few templates filled out with data from hundreds of records. Out of a total of around 600 pages, there are about 4 actual different templates. This data is all legit, and that is obvious to a human visitor. What I am worried about is a SE spider doing a filesize count on these pages and then getting the wrong end of the stick.
Is this a justified worry? If so, what can I do to get around it?

Cheers, Robin

[caine]

If a human can see the difference, then SE's should'nt have any problems, to put it another way, templates / style sheets, etc, take us away from designing each and every page independantly, more time for page opto's.