I just finished an Afghan for my daughter. I used the "Designer Shawl" pattern created by Karin Skacel Haack. I had to add on to the length and the width in order to make it 48"x70".
I used Noro Kochoran yarn for the bulk of it. You can see white flecks in the picture - that is simply a fairly fine mill end white wool I used to make it a bit bulkier and to create more interest.
I think the finished afghan weighs in at about 25 pounds. No wonder it took so long to deliver it!