Sainsbury's are currently offering triple Nectar points (6pts/£ on purchases of Gift Cards instore.
The gift cards are available for a number of different stores:
Toni & Guy
Arcadia Group (Burton, Dorothy Perkins, evans, Miss Selfridge, Topshop, Topman, Wallis)
So, if you plan to buy stuff from any of the above stores, you can effectively earn nectar points on those puchases by first getting a gift card from Sainsbury's (with triple nectar points), then spend that gift card at the other store. And of course if you're planning to shop at Debenhams, you should earn your normal points there in addition.
I really couldn't sort out which retailer to list this under, as it could apply to so many, so I put it here as the Nectar points are the main attraction, as it were :)