I'm pregnant with my second baby (due in May) and leggings have been a wardrobe staple for me this season. Trust me when I say I've tried a LOT of brands. But while plenty are comfy (Liz Lange for Target, Motherhood Maternity), most pairs don't look that polished after a few wearings. Either they look too much like sweats, or they're too thin, or they pill too quickly.
Ingrid and Isabel’s Belly Leggings are the answer. They give full coverage, never stretch too thin, and have a super comfy top that actually stays up. They retail for around $50, so they’re not "budget", but for the amount of wear I’ve gotten out of them, they’re totally worth it. Plus, a good friend assures me that she's still wearing hers six months after giving birth, because they look so good and the stretchy fabric still stays up around her slim-again middle.