I have Hold'em Manager, Tournament Manager, PokerStove(free), SnGWizard, AutoHotKey.
Hold'em Manager - Just like Poker Tracker, keeps track of wins/losses and statistics of yourself and people you play with.
Tournament Manager - Tracks MTT and SnG results.
PokerStove -
equity calculator. Runs simulations to determine how much equity one hand/range has vs. other
hands/ranges.
SnGWizard - ICM Calculator. Evaluates push/fold decisions in SnG's using the Independant Chip Model.
AutoHotKey - Automation software. Custom scripts for AutoHotKey allow you to automate and "macro" certain functions when playing poker. A common script is BetPot, which allows you to bet in relation to the pot just by clicking the right mouse button.