Yet another expansion is coming out. It's like, what, the fifth after what Donald X said would be the last one? Can't deny that I'm happy about it, though. It remains an extremely well-designed game.
Ancestor of the entire "build your deck during the game" genre, and for every new entry in that genre I've tried, I've thought, "yup, now I know there's a good reason Donald X. Vaccarino didn't do it like that in Dominion".
Works equally great as an over the board family game with more than 2 players as a highly competitive online 2 player game, too. That's pretty amazing, really.
You can play the expansion now! It's available for a few days in preview mode, named Plunder. Very money focused, with a 'loot' pile that's essentially 30 golds with actions like Discard down to 4, play an Action from your hand, etc! Very good fun.