re: your subject line - my dad also likes the same piece of doggrel, which I recognised immediately. It must be embedded somewhere in the 1950's SA culture, I'll ask him where it comes from.

We also enjoyed Thor enough to see it twice. I also really liked the characters, and found the whole arc an interesting psychological metaphor.

Spoiler warning - It was so sad when he couldn't lift his hammer.

I liked the whole blurring of advanced science and magic, the 'hammer forged in the heart of a dying star' sounded like neutronium to me, until I read this on the dangers of neutronium..
http://io9.com/5805244/what-would-a-teaspoonful-of-neutron-star-do-to-you

Finally you aren't missing much without the post-credits scene, it was very short, and didn't add much.