Pine and cedar shavings should NOT be used for bunnies. The urine mixes with something in the wood and gives off a cancer-causing gas which will kill a bunny or any small animal over time. See www.rabbit.org as the House Rabbit Society has sent out an alert on this.

Any paper-based litter is great, but kind of expensive. CareFresh and Yesterday's News are excellent and what I use. Corn Cob based litter does nothing to control or absorb the urine. There is a wheat-based litter on the market now but I haven't tried it yet.
The baking soda really helps with odor control.

Hope this helps.