Planet Bike Fast Freddies. These are the hybrid bike size. It allows me to go up to 700x28, perhaps a tad bigger.

Ask your LBS about clearances on your road bike. Most road bikes these days only have clearance for 700x23 and a piece of gum, not fenders, so make sure you measure carefully before buying. Planet Bike makes an identical set for road bikes that are narrower. Since mine is a mutant road/touring/cyclocross mostrosity, I had room for bigger tires and fenders.