Hidden & Dangerous 2 for a difficult good long semi-realistic singleplayer squad based tactical WW2 shooter. Really good sound, pretty free-form approach to most missions (disguised throat slitting or daring flanking assaults, both work). Could be compared to a Rainbow Six game set in WW2 with the British SAS instead.
Mafia, if you missed it the first time around. Very good plot based third person action game set in the 1930's. Should be pretty cheap. Take it for what it is, and not as a "GTA set in the Prohibition" (which it ISN'T), and it's a fine game, especially if you like vintage cars, gangster movies, Django Reinhardt music, and Art Déco architecture.
Tried Prince of Persia yet? Third person, but one of the most surprisingly good games I've played this year. Very good if you've got a dual-analogue gamepad. Seen it for as low as 30€. Should run well.
Indiana Jones and the Emperor's Tomb was very fun for a Lucasarts published license based game. I've seen it very cheap (15€) here. Not many puzzles, but insanely fun fisticuffs, beautiful level design, and mostly it just "feels" Indy (unlike the many LEC SW games, which are just clones of succesful games with the Star Wars license slapped on). Should run very well on your setup.
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Lost in a flood, run red with your blood
I've just locked an open door. Strange, yet symbolically compelling!
If it breaks, you get to keep both pieces.