For PC check out the following.
Planescape: Torment
Baldur's Gate
Baldur's Gate: Tales of the Sword Coast (expansion pack)
Baldur's Gate II: Shadows of Amn
Baldur's Gate II: Throne of Bhaal (expansion pack)
Freedom Force (heh, this a good game but i'm not sure if it's really considered an RPG
)
Icewind Dale - dugeon crawler
Icewind Dale: Heart of Winter (expansion pack) - dugeon crawler
Icewind Dale II - dugeon crawler
Neverwinter Nights
Neverwinter Nights: Hordes of the Underdark (expansion pack)
Neverwinter Nights: Shadows of Undrentide (expansion pack)
The Elder Scrolls III: Morrowind
The Elder Scrolls III: Bloodmoon (expansion pack)
The Elder Scrolls III: Tribunal (expansion pack)
As for the ps2 i can name a few good RPGs. The first 3 are tactical types and the last two are more dugeon crawler RPGs.
La Pucelle: Tactics
Disgaea
Growlanser Generations (This is basicly Growlanser II and III in one package.)
X-Men Legends
Summoner 2
Lastly all the games I mentioned but X-Men Legends, Summoner II, The Elder Scrolls and Neverwinter Nights games have a 2D art style if that matters to you.