SEO - short URLs vs longer PHP URLs

[nic.lk]

Is there any real SEO benefit from simplifying my PHP urls to shorter, neater urls (with mod_rewrite)? I want to do this mostly to make my site look nicer - but if it's good for search engines, then all the better.
Is there any reason NOT to make shorter URLs?

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[redspace]

I don't think it is about short or long. What is important for any URL is that the URL is somewhat describe what the page all about. Every page in any particular domain must be unique otherwise it will become duplicate content. So the URL should be unique yet descriptive. URL is the first interaction point between search engine crawlers and content and therefore it must not be taken likely.