Any of the Source engine games should run great on the last few generations of MacBooks and iMacs. Half Life 2 actually ran fairly well on my old GMA950 based M

Any of the Source engine games should run great on the last few generations of MacBooks and iMacs. Half Life 2 actually ran fairly well on my old GMA950 based MacBook. I know Valve has added some bells & whistles to the engine since then however to target older Mac's they may simply disable some of those features when running on Intel GMA or X* hardware.