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I agree about the Broken Sword ones, but 1 and 2 are quite old. I recommend buying 3 first, and if you find you like the characters, get 1 and 2 and learn the backstory.
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I disagree about Broken Sword. I played the demo of 3, and it annoyed me so much I uninstalled it before getting out of the plane.
It was pure tedium. You may find it interesting if you like the Myst series, then again, I think Myst was better than this (but that's like being the best Cricket team in Antartica).