I love momtrepreneurs (and in fact wrote an article on the subject, see sidebar) and I especially love the baby legwarmers from Little Leggings by Lynn. My youngest has been in them since she was a few months old, and my almost four-year-old still loves hers.
The best thing about Lynn's legwarmers is that they cost only $8, a fraction of the cost of brand-name pairs (and your little one certainly won't know the difference). Lynn offers great customer service, and an excellent selection, which often includes holiday themes. This ups the cute-factor significantly --I'm a sucker for holiday-themed accessories!