This looks super interesting. So far I haven't come across a battle system worthy of Chrono Cross so I'll check it out.
Now... as for a game that has stood the test of time. I mean, Chrono Cross is still an excellent game and I would definitely play it once again. However, since I'm the kind of player who has troubles even finishing new games, I can't say there is any game I would play years to no end.
Still, there are some games that certainly haven't lost their charm, even though they most likely can't offer anything new gameplay-wise - mostly because I have played them so much. Off the top of my head:
Digimon World 1. Doesn't matter if you were a Digimon kid or Pokemon kid; or any other kid, this game is one brilliant attempt at a proper monster "management" game. The leveling (=training) system was simple and straightforward and at the same time very powerful and interesting. The same thing about evolution. No levels, no stupid XP, no set path, just you shaping your digimon as you play. The story - it was ok, I guess. The graphics - beautiful. The sound - admittedly, can get a bit annoying at points. I'm still hoping they remake this game with added content. True, the battle itself wasn't that good, especially at the start of the game when you have less Brain stat and techniques (learn Ice Statue or Megalo Spark and you win the game), but the excitement of waiting for the screen to freeze and your digimon evolving - worth it.
Heroes of Might & Magic: 4/5: TotE - never too old for a quick Hot Seat with a friend. The campaign - better in H4; kinda bad in H5, but worth playing if you simply want to get some overpowered endgame heroes. Now where these games really come to their own is multiplayer. H5: TotE is still, after all these years, largely uncharted territory when it comes to possible hero builds and strategies. It has a very good skill system, easily the best in the series. The graphics - I like it, but certainly not for everyone, since it's kind of cartoony. When it comes to music, Heroes has always shined and H5 doesn't fall behind its predecessors.
If only you played Lineage 2.