I just bought Half Life 2 (+ Half Life 2: Lost Coast). Not a game that I was particularly interested in, but I heard so much about it over the years that I feel like I ought to give it a chance. It's only 4.50 euros at the moment anyway.
So that brings my total number of bought games up to five. I have to say that The Elder Scrolls IV: Oblivion was well worth the money. I already got around 50 hours out of the game and I haven't even bothered too much with the main quest line, nor the extra expansions that came with the game of the year edition. In fact, it feels like I haven't even seen a quarter of the game.