Some software I've been meaning to talk about lately:

Poisoned -- A P2P open-source file sharing application that aggregates "FastTrack (Kazaa, iMesh, Grokster), Gnutella(LimeWire, BearShare, Shareza), OpenNap (Napster), and OpenFT". If you really feel like paying for it, they have links to the EFF among others. One thing I find interesting about this app is that everybody has the username "poisoned" so who will the RIAA sue?

LaunchBar -- surely this has been blogged before here but LaunchBar is an app switching utility that has an uncanny ability to know which app you mean. I find myself using Expose and command-tab more now but others I know swear by LaunchBar.

iSeek -- Puts a search box in your menu bar, allowing you to search Google, Dictionary.com, and wikipedia easily.

iChatStatus -- a great, dorky little open source app that will display what music you're listening to (from iTunes) over iChat.