I have used the hard annodised sprockets before and they definitely last longer, the one I'm waiting for is the new twin ring sprocket which is currently only available for off road bikes but B&C / Renthal are planning to introduce for road bikes, see the link:
http://www.renthal.com/twinring.asp
In the meantime,I've just ordered one of the Super sprox from OTR these should last really well as they use steel teeth
Let me know what you think to the chain capt as I'll need a new chain shortly