Well that's certainly debateable.
For years SNES was king for me (and still a very close second) but nothing on the SNES can compete with Persona 3 & 4 (especially 4). Then you have Dragon Quest VIII where we finally get a presentation on par with gameplay (actually exceeds it, not a huge fan of Toriyama but the graphics engine was just so lovely and the voice acting was very good).
Then FFX and FFXII. FFIV will probably always be my personal fave but FFX and FXII for me are up there with Square's best. And FFXII's system beats random encounters ANY DAY.
On the strength of those 5 titles alone (FFX, XII, DQVIII, Per3/4) the system is a powerhouse. You also have sequels for Suikoden and Wild Arms plus the Xenosaga trilogy, Star Ocean III, and others.
But wait there's more: PS1 backward compatibility means FFVII, IX, Suikoden 1/2, Persona 1/2, Chrono Cross, FF Tactics, Vandal Hearts, Xenogears, Star Ocean 2, Grandia, Lunar (awesome special edition too), DQVII, AND ports of FFIV, FFV, FFVI and Chrono Trigger (only the SNES' cream of the crop!).
So really, PS2 is the RPG gamer's system.