Melodies are nice. But the ones that work the best for me are the ones where the writer has really nailed the words in an original way which no-one else could. Brian Bedford (writer for and singer in the group Artisan) is one of the greats for me.
Jeri, I'd take your thoughts about wanting to sing the songs, and turn it inside out. For me, the sign of a truly powerful song is one where I *can't* sing it - because I'm at risk of totally losing it with the emotions involved. With those ones, I have to practise the song so much that exposure to the song deadens the metaphorical nerve-endings slightly. The three which have got me the hardest on this are Steve Knightley's "Galway Farmer", Randy Crawford's "Almaz" and Guy Clark's "The cape". The latter in particular is seriously relevant to me because having lots of friends much older than myself and with my parents being pretty adventurous, it really sums up my feelings about them all.