I've been using Sylvania's dimmable compact flourescents. You can buy them at Menard's in the Chicago region.
The price is competitive about $8.50 - $9.00 per bulb, however overall, I feel they are way overpriced as a product - Menard's is well priced compared to others.
They do not buzz, however, they dimm only fairly well.
I have however, had significant problems with non-dimmable bulbs ($4.50 each) for ceiling fans and candle stick types in fixtures meant to dim. They buzz, flicker, etc....