Well, if you think 3.5 or even AD&D is fine, then youve got no reason to ever buy a new system.
Here in Sweden, most people still play "Drakar och Demoner"* from 1991 even though there have been 4 new editions since then.
* Its a game of its own and not a translation of D&D, they did choose the similar name to cash in on the hype though. The first editions (1982) was a translation of Chaosiums Basic Role-Playing, it then grew into something completely different