This is hard. Like, really impossibly hard. I suppose I've played hundreds of games since the early nineties, possibly even more - I seriously can't narrow it down to just the top 5, as there were so many great games!
I'll mention five titles I remember dearly and still consider them to be amongst the best I've played, but I won't number them and I wouldn't say, these are THE BEST... just AMONG THE BEST (my personal best, that is):
- Outcast
- Sam & Max Hit The Road
- Wing Commander 4 - The Price Of Freedom
- MechWarrior 3
- Steel Battalion
Honorary mention goes to "Jurassic Park: Trespasser" - what a horribly buggy and downright
terrible game it was, but chock-ful of all sorts of innovative features and unique gameplay mechanics for a 1998 game. It really was years ahead of its time and could have been a truly amazing game if given a proper amount of polish. I still love it, though.