I didn't play COJ at launch as I had inferior hardware, so when I got to in in late 2008 and was able to play it post-patches in DX10 I was blown away. Sure, the first level of Billy and Ray are extremely buggy, but after that I had no issues with the game.
There are just epic moments in that game that only come every couple years for me. Climbing that cliff to reach the eagles nest and looking outwards at the world is one of THE most memorable gaming experiences I have.
There's something about COJ that you won't find anywhere, and I am praying that COJ: Bound In Blood lives up to the legend (in my eyes)