You'll be lucky as this is a changing volatile subject. However no ships have banned smoking yet, but curtailed it in Public Rooms & Cabins, some only allowing it on certain open deck areas.
Have a look on www.cruises.co.uk and in the right hand column under cruise info there is a section on smoking policy.
There is a site that does a very good attempt at providing this information but unfortunately my earlier posting with the details has not been published. If you post details of the lines you are considering then I am sure you will get plenty of feedback or possibly you could do a search using the keyword 'smoking' in the search box of 'Find a Question' box.
You'll need to find a fairly active site because there are changes occuring almost weekly with this.
Someone asked about a cruise in 2009 and there is no way anyone could predict what the situation will be in October let alone next year. ... Neil.
Example, Thomson May 08 brochure states no smoking in cabins or any inside lounge but July 08 brochure now says smoking is allowed in cabins (but strongly discouraged) and smoking is allowed in 1 lounge. Best thing to do is telephone the crusie line you are interested in. Regards.