I loved Gothic 1, 2, the gold edition. Few other games do so well at creating atmosphere. Walking around the Old Camp in the evening, seeing people play the guitar/lute, people smoking; heck, it already had what The Elder Scrolls series wanted so badly and then had to reinvent worse and call it 'radiant AI' so that it got a check from the marketing department under 'sounds cool and hip while not costing us money'. Gothic developers knew all along that you could just script a day in the life of an NPC and it'd fool anyone good enough so you don't have to come up with some shitty AI that fails most of the time anyway. And once you got past the horribly clunky controls (seriously, what was it again, control + w or e to open a chest?) combat was just plain awesome. Your stats mattered, your armor mattered, your weapon mattered, but in the end if you sucked, you'd still die horribly. And it was one of the first games that actually made dark forests be dangerous and scary. And dark.
I tried really hard to get into Gothic 3. I installed mods, tweaked everything. But in the end, the core is just rotten. They got the whole idea of 'friends' completely wrong. The guys you met in Gothic 1 and 2 weren't your palls who tagged along with you; they had their own motivations, their own goals, and once in a while you met them, got strung along in their stories, and they at the end in yours. Gothic 3 screws them all up in appearance and voice acting, brings them all along for no reason at all, and puts you in a sandbox world filled with copy pasted villages where you have to kill massive amounts of orcs all the bloody time.
Risen, on the other hand, I quite enjoyed. The combat was decent, at least not as horribly screwed up as in Gothic 3. Also, there's a Risen 2 in the make. With pirates.