A few months ago I made myself a fall lapghan. I love this blanket and it keeps me down right toasty in the cooler months!
I adapted my favorite baby blanket pattern and added the edging from a pattern at Red Heart that I am using to make some Christmas gifts this year. The edging created a really nice finish.
For an adult lapghan I stitched 58 for the initial row (instead of 52 as listed in Melanie's instructions) and used 2 big balls of Harvest Bernat yarn and about 3/4's of a Big ball of Pumpkin Bernat yarn.
If you wanted to make a full size adult blanket rather than a lapghan, you would need about 3 Big balls along with 1 big ball yarn of your choice for the edging.