Great question, Mark!
I can't really give any objective views, as I married my first love! *awwwww* So, I haven't noticed any common traits in people I've been attracted to 'romantically', because there's only the one! Lust, on the other hand...
Gee, that really added a lot to the discussion, didn't it?
I'll be interested to see what others have to say.
In the very beginning, I guess I found the musician/filmmaker/artist thing appealing, and the sweetness and shyness, and the not giving a flying fig about trying to fit in with whatever's cool at the time.