The 10-20 is good for landscapes, interiors and usually is found stuck to my D200 for most part of the time. You see a shot I took in Monaco with the lens here: http://www.cameralabs.com/forum/viewtopic.php?t=2852
I did consider the more expensive options of the 12-24 by Nikon or Tokina, but settled for this. The extra 2mm makes a difference and the cost as well. I don't see myself moving onto a full-frame for the next few years, so the 10-20 was a no-brainer. Only 2 complaints with it though - if you're using ND grads for landscapes, you can't employ stacking with this as it vignettes. I purchased a wide-angle holder made by Cokin just for using my grads. And secondly the lens cap is horrible - you can't remove it with the hood on, so I had to buy a pinch cap made by Nikon to replace it. Otherwise tremendous value, especially if you solely take landscapes.
What do you mean by "if you're using ND grads for landscapes, you can't employ stacking"?