I thought I would put the big myth about duplicate content to trial. On the following domains I placed the same content at the same time: http://dxuh.com http://findscriptsonline.com http://esbro.com When I did so, findscriptsonline.com was PR0, esbro.com was PR0 and dxuh.com was PR2 I checked their google rankings here for my keyword of choice: 'domain name renting' just today dxuh.com (which had not appeared in the search ranking for any keywords until now) is on the first page and ranked 7th! It also has maintained its PR2.
1) No one even searches for that keyword phrase "domain name renting" - according to google's keyword tool, not a single search - so experiments with non-competitive keyword no one else is trying to target will give much different results than competitive keywords. 2) Google will pick one site to rank for duplicate content - it doesn't even have to be the original provider, just the one google feels is the most important. Given that the one with PR is ranking, it isn't a surprise.
My understanding is that what effect SERP is backlink to the site is more important than the uniqueness of content. But original content is what you should also provide. This may not a major influence but it still helps a lot on search engine rankings.
I feel that producing uniqie content as must do in SEO is quite over-rated feaxture. I saw first hand how duplicated contents, that have been submitted to lot's of article directories, helped the rankings. I do beleive that one has to be a bit careful about it, not to duplicate content from the targeted URL (Imean, ther one that we want to promote in SE) too much. But you can do it with articles, no doubt about it