Nikon Coolpix P500
It seems we're in the midst of a full-on zoom lens war. The last couple years have seen manufacturers cram longer and longer lenses into compact camera bodies. While I wouldn't say this is a good thing, it's certainly something consumers want.
The two that currently rank as the longest are Canon's PowerShot SX30 IS and Nikon's Coolpix P500. Going just by their magnification numbers, the Nikon comes out on top with its 36x f3.4-5.7 21.5-800mm lens (35mm equivalent). However, the Canon doesn't start out as wide, so its 35x zoom is longer, going from 24-840mm. The Canon has a brighter lens, too, starting at f2.7.
Lens specs aside, the Nikon gets the edge on the Canon with fast shooting performance and better design. The Canon has better photo quality at its lower ISO sensitivities, which resulted in a higher photo-quality rating, but not by much. Neither are great above ISO 400, so low-light photos are, well, not great.
Still, if you can overlook their photo faults, these cameras and their lenses are pretty incredible given the price, size, and weight of the cameras. And for those who maybe don't need the longest lens, but want more control over final results, check out the Panasonic Lumix DMC-FZ100.