The Package Advisor
Have you seen this page on the RPA wiki? The Package Advisor. Popular stable packages categorized, advantages described, flagged if packaged. I think this could be a nice starting point for a fledgling Rubyist. Kinda like a buffet table: I come to pick out a web framework and, while browsing, I find a database connector and a lightweight markup.
It would be great to have a page for each package where users can leave feedback and describe any problems with the installation.