Well this question sure started a lively discussion!
The only issue for me is where do you find the best in slot item of each time. Using BG2 as an example, when I replay that game, I know where to get the best helm, the best ring, the best 2-hander, the best boots..etc.. for my build. And I don't like that so much. I would prefer to have to take out various boss mobs until I find which one has the best longsword this time around. Lesser, leveling gear I also would prefer to have randomized, although having some of it fixed so that someone wanting to make a bastard sword user won't end up going too long before finding any bastard sword.
But for boss mobs, I really don't like knowing where to go to get all my best-in-slot gear. Even something as simple has taking a group of 3 different bosses in one region of the game and having 3 nice designed items that gets randomized among them so that you know one them will have that helm you want, but you won't know which one has it on this play through.