I would buy (and did) this laundry bag from Crate&Barrel.
I've been eyeing this bag for at least two months and finally ordered it yesterday. Right now I use a big plastic basket that works fine, but I hate sorting whites and darks on the floor. No matter how often we vacuum, dog hair inevitably gets on the dirty clothes and doesn't always disappear into the lint trap. Plus, the bag got fab reviews and I love the playful design. Reviewers said the front pocket held plenty, so I plan to use it for tops that require special care (I usually only have one or two of those per load, so they should fit). Anything to make laundry a little more fun is welcome in my house!