If you're into dSLR photography but don't want to carry around a bag full of lenses, Nikon has introduced a new lens just for you: an 18-300mm f/3.5-5/6 G ED VR DX lens. This is the longest focal length range in the Nikon lens system and gets you the 35mm-equivalent focal-length range of 27 to 450mm. That means from moderately wide angle to super telephoto in one lens. And if you need something wider than 27mm (which would be nice), just add a super-wide zoom to your kit and you'd pretty much have all you needed in two lenses. I've yet to try any of Nikon's all-in-one zooms, but this one is pretty tempting. The lens has a variable aperture of f/3.5 to f/5.6. The lens will be available at the end of June and the price (I think this is suggested retail) is $995.
By the way, as of this year, Nikon says that is has now manufactured 70,000,000 lenses. I think if you stretched them out end-to-end they'd probably circle the Earth quite a few times! Shall we try?
All about lens apertures: If you'd like to learn more about lens apertures, lens speed and why some lenses are faster than one another, have a look at the multi-page Lens Aperture Primer on my main site. It's probably the most extensive aperture tutorial online and it's free, of course.