List of tools

Please add your own, or add someone else's.

EVE Fitting Tool (EFT) - Ship Fitting Tool
EVEMon - Skill Training Monitor, Planner, etc
GtkEveMon - Skill Training Monitor, Planner, etc, but for Linux and GTK+ enabled systems
Eve-MEEP - Tool for industrialists
Eve Market Monitoring Application (EMMA) - Wallet Data Analyzer
EVE Launcher - Tool for managing multiple EVE instances
EVEMover - Tool for managing multiple windowed EVE instances on multiple monitors
POS-Tracker 2.1.0 - Web-based (php/mysql) POS tracking
Research Database (RDB) - Not free.
Cargo Calculator - (online/ingame) Calculator for cargo volumes (Note: Trinity changes not yet included)
EVE Commander - Access all your character information offline - transactions, assets, market orders and skills.
Bellatroix' Item Comparison Tool - Compare any item against any other and build shopping lists.
Bellatroix' Assets Viewer - Load and view all of your assets and market prices for those items.
eve-mail.net - In-game account creation for: E-Mail & XMPP/Jabber-based IM with shared contact groups and an API-enabled IM bot.
EVEPOSTimer - Track reinforced timers for friendly and hostile POSes.