I already played the hell out of the series starting with 2, and 4 was the best in terms of hosting an online game and being a game designer (they removed some functions in later games), so after that it all all downhill for me.
By "being a game designer", I mean being able to use host powers to enforce rules for made-up games. My server was quite popular because I invented a system that rewarded people with points for doing well in games, which they could spend on no-points-earned games of their choosing or map changes. Of course back then it was a lot easier to tell how popular a server was because not many people bothered to get their PS2s online.