I chose "Lady in my Life" from the list in the poll. I think it's lyrically superior to most of the others, although I do love the rich, bohemian sound of "Liberian Girl".
Songs that I think are also VERY romantic, but are not on the list, are:
For All Time
Beautiful Girl
On the Line
The Way That You Love Me
Best of Joy
"For All Time" is a HUGE favourite of mine, amongst these romantic songs.
If we're looking at heart-breaking romantic songs, I would choose "She's Out of My Life" and "Don't Walk Away".
Also "Fall Again" gets an honourable mention, even though it feels (and is) unfinished.