I just bought a walmart blanket despite wanting one for the past several weeks. I found phineas and ferb and it finally became worth the $22 investment.
They are huge, warm, and softer than I thought possible. Big enough for any adult and the graphics are fantastic. They also have prints that normally don't make it into juvenile and adult items such as cars and toy story.
Walmart.com: Disney Phineas and Ferb Fleece Blanket, 62"x90": Kids' & Teen Rooms