1. KotOR
2. DA:O
3. BG
4. BG2
5. ME2
6. ME
7. NWN
8. DA2
Frankly, I never understood why the BG games are so highly praised. When I played them, I liked them, but they were IMO largely overshadowed by FO 1+2 and PS:T and I remember being very disappointed by their fake dialogue choices and lack of C&C, at least compared to e.g. FO2. (This comparison is probably the reason why BG does not gain any nostalgia points).
KotOR completely took me by surpise. I hardly read anything about it but I was in a "buying mood" and decided to treat myself so I purchased it (due to the SW setting) not expecting too much. Having no expectations at all, I was pleasantly surprised and it was a very enjoyable experience. But truth be told, the main appeal to me was the SW atmosphere, jedi powers and light sabers.
DA:O I enjoyed very much. (Again I had no expectations as I deliberately avoided to read any previews in order to prevent any hype). To me, the biggest virtue was the fact that they did not use the D&D ruleset. (Although I understand that for others that is a shortcoming). I am familiar with the D&D ruleset but over the years I have come to dislike it, especially the magic system, which I passionately hate. Also, DA:O had more C&C than BG (at least if my memory serves me right), which is the main reason I rank it higher.
I recently played Mass Effect and I had high expectations because it had been praised a lot. I was unimpressed and I found it an OK game but average in many aspects. I like the setting though.
Mass Effect 2 is about "packaging". Though enjoyable as a cinematic experience, but take away the high production value and you are left with an empty shell.
I found NWN to be very bland and boring.
DA2, well, what can I say that hasn't been said before?
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