First, you're using a crop lens on a full frame, so your wide end is actually the same viewing field as a 29mm on full frame. The body is simply using the sensor in crop mode.

This one gives you the same on the wide end as the 18-55mm you have, because it's an actual full frame lens. https://www.nikonu....5-5.6g-ed-vr.html

If you want even more zoom, your only option is a permanent lens zoom camera. They pack a serious lens and the amount of details you can capture with them while keeping an unassuming entry-level DSLR appearance is amazing.

This one has 28-600mm full frame equivalent with F/2.8 throughout.
http://shop.panaso...as/DMC-FZ200K.html

My most used lens for exploring is the Nikon 14-24 f/2.8 I was using it on my D300 and now on my F5 yes it's a beast but it feels good in the hand and on the tripod.

But I do second the suggestion of Primes and going Sigma, I'm actually planning on getting one of the 24mm units soonish.

As to answer your question on what lens to use...use the lens that will get the results that you want. Remember you can (in most major cities) rent different lenses, take them out for a spin, just like a car. Give 'em a test drive.

Posted by Axle Remember you can (in most major cities) rent different lenses, take them out for a spin, just like a car. Give 'em a test drive.

That's just what I did when I was hesitant about buying my first expensive wide angle (at the time, it was a Canon EF-S 10-22mm)

I wanted to know what it was like to use any kind of wide angle lens, but also knew it was what I needed in order to get the shots I wanted. So, I waited for some vacation time and bit the bullet when my four day epic journey arose that could not have been accomplished without the rental.

And actually, it only turned out to cost like 50 bucks for four days. They gave me a Pelican case and everything, with local pickup and drop off at Hunt's.

Is this not better than impulse-buying a 679 dollar lens without ever having tested it out first? I would say yes.

(I did go ahead and buy that lens a day later)

I've been using my 24mm on a crop (so like 38ish iirc) and it's been a pretty solid lens choice. It's wide enough to get what I want and has a fairly large aperture for when I choose not to bring a tripod for semi-low light stuff

Mirroring what other people have said:
1. Rent some wide angles, fisheyes, and primes - you'll never know what you'll like until you try the gamut.
2. It all depends on the type of shot you're going for: scene shots require wide lenses, detail shots typically require lenses with high apertures.

My 3 go-to exploring lenses are a 17-40, 15mm fisheye, and a 50mm f/1.8. I don't shoot Nikon, but I'm sure there are comparable lenses available.