What useful crop can I grow in front of my house (shaded), which also looks good?

Do you mean veggies of some sort? I have 2 rhubarb plants which grow in the shade happily. They are the variety that is good for "forcing" though. They grow quite big and the leaves in mho are stunning. Alternatively, if you're after plants, I have borrowed books from the library on growing plants for shaded gardens.

I tried rhubarb there once! Perhaps not hard enough, and yes it was veggies I had in mind

The best way to get rhubarb growing is to plant it with manure and water well for the first year until the plant is established. Have another go! And try getting the variety that is good for "forcing". It was either dobies or suttons that mentioned. If not, try "froogle" for rhubarb and read the blurb on the different varieties available. Good luck!
ps, why not try your local library for books on veggies and see if any are ok on shade.