I think the best time for me was right in 1991 - I was most excited about King's Quest 5 and Space Quest IV then... those two games, at the time, were mind-blowingly amazing. I had been playing Sierra games for years at that point - watched them grow from AGI to the first 16 color SCI games.... but that leap into 256 colors was amazing. At the time, I remember there was some kind of consortium of computer manufacturers, peripheral producers and game producers that established the stats of what they called at the the time MPC - Multimedia Personal Computers - compliant. I remember Ken Williams talking about it. CD-ROM drives were new and amazing, and the soundcards you could get were new and mind blowing. I was 13 years old - and it was such a change. PC games took a leap over the SNES and Sega Genesis at the time with these kinds of games - I didn't even have a computer that could run them at the time. I had to go to my buddy Bryan's house to play them.
Right there, in 1991 - it was the cusp of the new gaming era yet, I could still enjoy my beloved classics. I remember, I got QFG2 for Christmas in 1990.... I remember thinking that it could have been in 256 colors too, at the time. Had it started production a little later, it probably would have.
I played the hell out of KQ5, QFG2 and SQIV that year.