One major problem with your poll:
Not everyone has played all those games. I can't judge whether a game is good for RP or not if I haven't played it. That's going to lead to skewed results.
There's no way to get around that. You can adjust the weight given to this or that game, depending on its popularity and how many people have played it, though. For instance, I'm pretty sure Icewind Dale ranks too low in the polls, but that's likely because it's less popular than NWN or BG.