Broken Sword 1 = Best game ever.
Agreed.
I loved the second's Mayan theme, although it wasn't the masterpiece Broken Sword 1 was.
The humour was a bit too "zany" at times and the music didn't impress me as much. I also missed the first's hub structure, that it all centred around Paris.
The third was fairly good. I didn't like the way it pretty much became fantasy, instead of the Conspiracy-esque atmosphere, with a hint of the supernatural, like the other two.
Although I did like that it developed Nico a bit.
Have to say I'm looking forward to the fourth one myself, coming out Spring this year in case you haven't heard.