Papers 1.5!
I use Papers to organize all of my, well, papers. I read a lot of journals regularly, because I have a lot of interests; without a good workflow, I’d get buried under a pile of PDFs (admittedly, not that heavy, but >1,000 PDFs is hard to manage, no matter what the organization folder system).
The new version is much better. It integrates with more search services, such as Google Scholar, Scopus, and Web of Science, and the organization system just got a lot easier. The search integration with Spotlight is much snappier now, there is now even better BiBTeX integration, and lots of bugs seem to have been fixed, as it hasn’t crashed for me yet. There are still some small nitpicky issues (like not being able to specify a Smart Collection that gathers all papers imported in the last month), but overall this is a much more stable and useable release. Worth the price, especially with the student discount!