I know its becoming cliche to do lists like this but there where indeed many amazing games put out during that generation (the last "gamer" generation to me) but many of them where lost to the time. What do you think? mine would have to be a split between Ecco Defender of the future or and this will sound weird, Pitfall The Lost Expedition!
It was such a refreshing experience for me back in 2003-2004, a semi open world where there is no time limit! (i hated time limits in adventure games back in the day) but in all seriousness it a polished experience. It has some of the largest detailed and colorful worlds in a PS2 era title that has fulfilling level design and lots of replay time and mini games that are fun!
I think the thing that the game still holds over me after all these years is its personality, it has some very fun and well animated characters and cutscenes. Its something that may games today have lost, a truly family friendly game that has a well made script. You can tell they had alot of fun with this game due to just how likable it is. It also has a special place in my heart due to how much time i played it with my dad and the amount of jokes we took away from it, the one im putting below still has not stopped in 15 years, but really watch all the cutscenes in you can
Head for the 15:10 mark for the joke
If you had to play it on a platform i would recommend (and its the only time i will) play it on a PS2. For the amount of buttons the game needs it can be come kinda cumbersome on the Xbox or GC