Best wide angle lens for nikon?

Best wide angle lens for nikon?

Added (1). I shoot with a nikon D3100 and a 18-200 lens. I love my setup it was pretty inexpensive and i get great photos at half the cost. I tend to shoot more landscape and I think I want a wide angle lens for when I do go shoot landscapes and such and I was just wondering what lens would be the best? Price obviously is a factor because its just my hobby not profession but i do have a passion for it. Just double checking on what lens is best

I use a 12-24 mm Nikkor for shooting landscapes and architecture. Nikon makes a less expensive wide angle zoom(about $250 less), the 10-24 mm and Tokina makes an excellent 12-24 mm lens that may fit your budget if it is less than $900 to $1,225 (the cost of the Nikkor wide angle lenses)

Here are two samples which were shot with this lens.

You can also shoot overlapping images using your 18-200 mm and then merge them into a panoramic image

I'm a pro photographer and I discovered the Tokina 12-24mm and 11-16mm are very sharp, smooth operation and clear image.
However it is a DX lens and will not work fully with an FX full frame lens.
If you have a Full frame Body I recommend the New Nikkor lens 18-35mm for extra sharpness and clarity.
18mm at full frame is the equivalent of 12mm DX.

I've been looking for a wide angle lens for my Nikon D90 and I've settled on the Tokina 11-16mm. It is offered at a very competitive price and gets very good reviews.
http://www.tokinalens.com/tokina/products/atxpro/atx116prodxii/

The one from Nikon.

Simply get the lowest number of mm you can afford.