I honestly can't think of any "romance" in any game I played across the years that stuck with me over time.
I always try to chase at least one when the option is available (i.e. Viconia in BG2, Morrigan in DA, etc) but there isn't one that I can think back to with particular fondness.
I remember when in Bioware's Jade Empire by the end of the game if you picked the "flirty options" with both the female leads (and companions) across the entire game you suddenly had the option just before the final battle where both confronted you with a "We decided that choosing is not fun, so let's have a threesome" (and then it's basically a fade-to-black, so don't go in expecting much after reading this post).
If nothing else that was an amusing development and something different from the usual attempt to moralize because you didn't "stick with one", but that aside I remember very little of the two characters.
I also never liked the game very much in general and I think its entire cast was dramatically under-utilized, so there's that.
