A question I struggle with mentally when it comes time to deciding my favorites of the series.
I know ultimately, that PQ3 is my favorite for a variety of reasons. Nostalgia being a strong force to contend with here. The story itself though and the struggle to figure out the games without resorting to the red book of hints. PQ3 was one of the first PC games we bought, and I was hooked from the moment those elevator doors opened and Sonny Bonds steps out.
I actually then played the games backwards. My mom worked with a fella that has PQ2 and I remember her bringing home the disks so we could install. The copy right at the time limited my access to the game, but the one familiar face I was able to recall Jesse Bains. PQ2, again had me hooked, but the graphics kept me somewhat cautious about letting myself really connect to the game.
PQ1 was a gem for a few reasons. I played the original version, obtaining the disks from a source I can't remember. I played it, struggled with some of the specific typing commands the game was looking for (Scene with Maria in jail was one I remember I COULD NOT pass) but ultimately enjoyed it.
Then, they released the VGA version, and I was hooked. I loved it. The music, the graphics. It was excellent.