During some of my forum lurking, I spotted a WebmasterWorld Thread on the topic of the nofollow attribute and RSS feeds. Basically the member asks if he is better off using the nofollow attribute to hoard pagerank or link out to "quality sites that provide the news."
I replied to that question in message number three stating that the purpose behind the nofollow attribute was to give control to the Webmasters. For a site like this, a forum, a guestbook and so on, people can come in and link to anywhere without immediate moderation of those links. We all have our spam filters and such, but we do not immediately control the outbound links until we have time to moderate them.
My point is, if you syndicate someone's content through an RSS feed - you must think that content has enough merit and quality for your visitors. If that is the case, then those sites you syndicate deserve a clean link back, that is how the Web works.
During this site's upgrade, the nofollow attribute was automatically installed, I will probably pull them now, since comment and trackback moderation here is almost 99% solid now.