This gorgeous cotton blanket is currently stocked by Kmart. It's delightfully unisex, classic and such a nice change from the ubiquitous determinedly cheerful prints. And it's only $10!
As an added bonus, I've noticed that my living room looks less messy if the baby gear strewn around has more natural tones! However if brights are more your thing, you can see that they have two other great striped options.