Cel, +1, for the heretic quote
I think Deus Ex can be classified as an RPG however like Demigod, it is a cross between "pure" genres.
But I definitely see the point that it is an FPS with RPG elements, however the elements were fantastic. Morph, as Ryat mentioned Deus Ex was fantastic, DXII sucked - they removed the best parts of DX1 and consolized it. They are currently working on DX3 with the promise that it won't suck. We'll see though.
Some great games have been mentioned, bards tale is definitely one of my all time favorites, along with the eye of the beholder series, ultima, NWN, M&M, Oblivion etc.
A couple the I loved that aren't on here as well are:
Master of Magic (c64) was great to play, i think someone on the forums here uses the MoM cover art as their avatar,
Dungeon Master (Amiga) was a classic as well.
Stonekeep (PC) was just a lot of fun but more hack n slash as opposed to role playing.