ChessCube - A great website to play chess; a lot of players for a game anytime!
Chess.com - Another great website with tons and tons of Chess content.Chess Training
Chess Tempo - Tactics and endgame training with a lovely database of games and statistical information; also tracks your progress with various ratings and graphs.
Chess Applications and Internet Resources
Chess Flash PGN Viewer - Quick Publisher - This is how I post PGN's on this blog!
ChessQuotes.com - Wisdom and Interest
Free Chess Programs
Scid - A Free Chess Database App - Downloads for PC, Mac and Linux!
Arena Chess - A Free Graphical Interface - Only for PC.
ExaChess - Chess Database and Toolkit for Mac - A free ExaChess Lite download which is very functional. There is also a paid version available for purchase which increases its utility.