Waddaya mean, "Best ever"? There are sooooo many "best evers". . . .I do vote for Dick Gaughan's "Different Kind of Love Song". I know it's not all that romantic, but it needs to be heard. ;-)
For stuff from Bruce "Utah" Phillips, might I nominate "Nevada Jane". Has the virtue of being not only touching, but (mostly, I suppose) true.
Garnet Roger's "Frankie and Johnny" (AFAIK; it's on the "Small Victories" CD) is interesting for a slightly different take on love.
I could go on and on. . . .
Cheers,
-- Arne Langsetmo