Championship Manager. All of them, except dot$ (CM4). Ever since 92/93. Easily the best series of games to grace any platform.
SWOS gave it a run for it's money, though. A great game of it's day, and, if I was any good at it - I'd still play today. There's not a better all-round footy game (i.e. detailed management with playing) around.
Gran Turismo 3: A-Spec, for the PS2, is another superb game. Absolutely top-drawer. The bench-mark for racing games, and possibly my favourite game on the PS2. Only play it in short bursts now, but there was a point when I was addicted. Compared to the other Gran Turismo's, it offers a lot more play-time, and is a bigger game in general. Decent array of tracks, and F1 cars.
Commandos was class in it's day, but I think when I bought Hidden & Dangerous, Commandos was surpassed by high-res graphics. H&D is just as hard as Commandos (which made this game so quality) but comes together with gorgeously rendered graphics, and superb historical accuracy, and playability. Brilliant game. Medal of Honour has nothing on Hidden & Dangerous.