I agree with Crisgal, celery is wonderful as a vegetable accompaniment, especially to fish.
Try slicing it into 1/4" pieces, sauteeing in a little butter, then adding a little vegetable or chicken stock. It produces a lovely savoury, yet fresh flavour that goes well with pork.
Also, it marries particularly well with spices. Try sauteeing until transluscent, along with a few cumin seeds, or carraway, or fennel seeds. It's particularly nice done this way with peeled, deseeded and sliced cucumber too - just sweat the cucumber and celery together in a little olive oil with cumin seeds, fennel seeds, and finished with a little chopped dill. It's excellent with white fish.