A client of mine has a lot of differentiated landing pages with only a few changes on each, but with the same intent and goal as the generic version. The generic version of the landing page  is included in navigation, sitemap and is indexed on Google. The purpose of the differentiated landing pages is to include the city and some minor changes in the text/imagery to best fit the Adwords text. Other than that, the intent and purpose of the pages are the same as the main / generic page. They are not to be indexed, nor am I trying to have hidden pages linking to the generic and indexed one (I'm not going the blackhat way). So – I want to avoid that the duplicate landing pages are being indexed (obviously), but I'm not sure if I should use noindex (nofollow as well?) or rel=canonical, since these landing pages are localized campaign versions of the generic page with more or less only paid traffic to them. I don't want to be accidentally penalized, but I still need the generic / main page to rank as high as possible... What would be your recommendation on this issue?