Ugg only one game? Made harder because I like nice pretty graphics so while I have favorite games from the past I can't say how much I would enjoy them, even if it was for the first time. I did enjoy Pillars, Torment:ToN, and loved Tyranny though so some hope for the old games ... but they also look better then similar games in that style from the past.
Anyhow getting off track. If I go with my gut answer, the game that first came to mind, then it would be Dragon Age Origins. The graphics were good and the Mabari, Alistair, and Morrigan are pretty much 3 of my all time favorite companions.
I will just say, as a secondary runner up, perhaps Morrowind and Bloodmoon but only if I could upscale the graphics to modern graphics.