My friend, who quilts all the time and has made over 300 quilts, loves the lap quilts....size 50'ish to 60'ish inches. I'm still working on bed quilts for my kids and grandkids, so I prefer the larger ones. It is very important to realize how big the finished quilt will be when you are buying a pattern. If you are wanting to make a king size and the size is 60 x 78, at the most you will have a short twin. This is a chart I made up for myself because I wasn't sure how big I wanted to make things. It will at least give you an idea of how to calculate the size for the bed you want to cover.
These numbers were from multiple sets of books and internet verifications.