Here is a pic of the toffee I made over Christmas and never got a chance to post. I was pretty easy but it's really pretty essential to have a candy thermometer. I used the recipe from a book I've had for a while now, Brittles, Barks, and Bonbons by Charity Ferreira. I'd definitely recommend it.
I didn't modify the recipe at all so I'm not going to post it here. This recipe is really close to the one I used, though:
I would definitely add a little salt - maybe 1/4 teaspoon.