As a Jane Austen fanatic, I've read all six novels and seen nearly every film adaptation of her work, naming Ang Lee's Sense and Sensibility as my all-time favorite, with Pride and Prejudice (the Colin Firth/Jennifer Ehle version) a close second.
Becoming Jane -- an admirable, but not stellar -- fictional interpretation of Jane Austen's real life, starring Anne Hathaway (as Miss Austen) and James McAvoy (as her admirer Tom Lefroy), may not match the aforementioned in terms of rich storytelling, but the costumes, I must say, are my favorite thus far.
What I liked about Eimer Ni Mhaoldomhnaigh's designs were her fabric choices. Of course, there were the requisite brushed cottons and tulle, but there were also black polka dots on cerulean blue and delicate hand-stitched flowers on black calico. I'd say they pleased me even more than the beautiful designs in Emma, starring Gwenyth Paltrow. This picture doesn't do the black calico piece justice, but Hathaway and McAvoy do shine in the candlelight.