I know this is a Beyond Divinity forum but still your Top 5 lists seems strange to me. For me Beyond Divinity is not even on my Top 5 list and just barely on my Top 11. I list the number of times I have completed the game in brackets.
1. Baldur's Gate 2 / Baldur's Gate [4, 3]
2. Fallout 2 / Fallout [3, 2]
5. Neverwinter Nights with all expansions [1, 2, 2]
4. Divine Divinity [1]
5. Knights of the Old Republic [1]
Those five games are all good enough to be number 1 but only 1 can hold that spot.
6. Arcanum [1]
7. Plancescape Torment [1]
8. Morrowind [1]
9. Temple of Elemental Evil [2]
10. Lionheart [1]
11. Beyond Divinity [0 almost there]
I put Lionheart before BD because it was more fun to play although the second half what not so fun. Has the best quest system also. Neverwinter Nights including all the player-made modules it probably the game I have spent most hours playing. Play the modules Twilight+Midnight they are superb.
I cannot really say why, but BD just doesn't motivate me. The jokes are only half-funny. Not like in Neverwinter Nights:Hordes of the Underdark, or Arcanum which made me laugh a lot. Play Arcanum as a really stupid Half-Ogre, it is hilarious.
The deathknight is original and I am all for that if it makes the game better but in this case it doesn't. Skills are nearly useless which makes you care less about your character. The story is not interesting but many RPGs has that problem. Graphics and sound are OK but they neither makes the game better or worse in this case.
I dont consider Diablo 2, Nox, or Sacred RPGs. They are great games but I consider them Action RPGs.
I dont list really old games like Pools of Radiance, Curse of the Azure Bonds, Eye of the Beholder 2, Shattered Lands, or Menzoberranzan either. Shattered Lands is like a turn-based Baldur's Gate 2 but with psionics and a cool(hot) world. If you haven't played it you really should.
Currently I am half-way through Act 4 in BD and I just got so bored that I can't make myself finish the game. I am thinking about printing the last pages of the walkthrough and sacrifice the hours or less it takes to complete the game just to be done with it. Give me a reason to finish the game!