If something is new and improved, we say it is the best thing since sliced bread.

VOA: special.2011.02.20

The lake is where you will find the Chateau Lake Louise, which, depending upon your opinion, is the best thing since sliced bread or a lump of human intervention dropped into paradise.

BBC: The natural wonders of Banff and Jasper National Parks

Enter George Watson, a clever design guru with an engineering heart, who has crafted the best thing since sliced toasted bread, the Glide.

ENGADGET: Glide toaster gives breakfast bread a new flair