Same with Driver, Drakan and Shenmue, 3D open world games were already established in 1999.
Outcast is another one I didn't realize was from 1999 (next to Drakan). Somehow in my memory they should have released a lot closer to Far Cry, yet that didn't come until 2004.
Outcast was something special. I never finished it though, it was hard and I sucked at shooting in that game, not used to tps yet. The voxel based landscape was cool yet indeed very power hungry. I couldn't run it fully as intended until I upgraded/replaced my PC and by then I was sucked into Everquest.
Looking through the thread it looks like a runoff isn't going to change much even though Other is winning. It's all different games.
Votes per game
Pokemon Gold/Silver/Crystal 15
Final Fantasy 8 11
Super Smash Bros 8
Heroes of Might and Magic 3 5
Rollercoaster Tycoon 5
Shenmue 4
*Age of Empires 2 3
Legend of Dragoon 2
Donkey Kong 64 2
*Homeworld 2
*Soul Caliber 2 (which first released in 1998)
Silent Hill 1
*Alpha Centauri 1
*Gran Turismo 2 1
*Jagged Alliance 2 1
*Sim City 3000 1
*Resident Evil 3 1
*Quake 3 1
*Ogre Battle 64 1
*Everquest 1
*Chrono Cross 1
*Planescape Torment 1
*Unreal Tournament 1
*Freespace 2 1
*Tony Hawk 1
*The longest Journey 1
*Might and Magic VII 1
My re-vote would go to Rollercoaster Tycoon. I love building games especially without armies trying to destroy what you're building :) (Hence RCT winning out over AoE2 for me)