Yeah, Gothic 1 was great. I still think it's the best game from PB, even despite its controls being the wonkiest. They've certain gotten better w/ the controls over the years and all - but none of their games topped Gothic 1, IMHO.
Yeah, Gothic 2 was still pretty good - but still, Gothic 1 left the first impression, felt like something brand new at the time (especially w/ NPC's on schedules + the way they interact with each other) and left the most everlasting impression on me.
Gothic 3 could've been great, if it wasn't a bug-ridden mess back when it came out. Played the heck out of it, even despite it being a bug-ridden, poor-performing mess. At least it's way more playable performance-wise, these days and age.
Risen 1 is probably the best PB game they've done since Gothic 1, which in many ways is very similar to Gothic (i.e. it takes place on a very isolated area, a few factions, and whatnot). While Risen 2+3 have my preferred pirate theme setting, which I think they absolutely nailed - there's really something special to me about both Gothic 1 & Risen 1. The complete package of gameplay, atmosphere, choices, story, and whatnot with those two games when they dropped were something to behold, IMHO.