Some reef bones can be used for decorative purposes, but as Aquascaper said Live rock give you the 'natural' look and is a living filter. Just shop around for goos bits
Tends to be more expensive than 'normal' live rock too.......
The only LFS that selss it round here (and they are overpriced) sell Fiji live rock for £14.99/kg and Tonga branch live rock for £19.99/kg
I personally don't like it when it's mixed in a tank with other live rock as it looks unnatural and i've yet to see a tank with it alone that doesn't look somehow barren.