I have always been disappointed with winter flowering pansies. They don't seem to grow at all and I end up pulling them out in the spring to put in summer bedding plants. They are the same as summer pansies but just sown later in the year.
I have grown wall flowers from seed and bought them online as small plants. They seem to be very robust and have a lovely perfume. I don't think they would grow in a hanging basket though.
Skimmias (with red berries) and trailing ivy seem to be the preferred filler for winter pots and baskets.
I change the plants in my pots in autumn and spring. I don't have loads of pots. I am planning to plant dwarf narcissus bulbs. I do this every year. I prefer narcissus as they are perfumed.
Unfortunately, you end up with daffodil leaves taking ages to die back, which can make it hard to plant up the pots up for summer. I was planning to leave the bulbs in so that I didn't need to keep replacing them and could put annual summer bedding plants in around them. I have worked around this but last year I dug them all out and passed them onto a friend who was planting up a grass bank with bulbs.