And as for mod_rewrite being wonderful SEO-wise, I happen to disagree
errmmm... and I disagree with your 'disagreement'
7 years of doing SEO for clients and my own network of sites - some in highly competitive areas - and LOADS of detailed testing - leaves absolutely no doubt, SEO-friendly urls help a lot.
pedrotuga is completely right - it is not so much to help with spidering, (although it does), but more importantly it DOES make a difference in SE ranking.
I have mod_rewritten plenty of client sites that had urls as relatively simple as PunBB, and the difference in SEO ranking was noticeable - more pages spidered and bettter ranking.
Of course, there are site that rank well that don't have SEO-friendly urls, but that doesn't prove anything really - you need to take a before and after view of a mod-rewrite exercise to notice the value.