Baldur's Gate 1&2. I think their reputation came same way as Final Fantasy VII (another candidate), that they were to many people the first that kind of game they played so they remember them fondly. (OK, I'm guilty of the same with Phantasy Star.) They weren't really that different to earlier D&D games, nor better in various aspects.
The only even 9/10 part was the BG2 expansion Throne of Bhaal, at least they finished the series well. But even the forgotten sister series Icewind Dale was better in total.
Similarly, Star Wars: Knights of the Old Republic 1&2. Particularly the first felt very generic, you could've just change names and looks and call Force magic and it might've as well not been a Star Wars game. And I hate RPGs being linear; though the middle half of the games has several parts to play in preferred order, each part is internally pretty linear, as are beginning and end of games.
Western RPGs aren't my favorite genre, so I'm biased. But for example of Fallout 1&2 (of same era and genre) I can see why people appreciate those, even if I didn't hugely enjoy myself.