QUOTE (Sidney @ May 12 2006, 02:06 PM)
When you hear tooth here we are talking about the roughness that you can feel. So, a "buttery smooth" nib has tooth, but none that we can feel. Some like their nibs a little toothier so they can control their writing better.
Sidney hit the nail on the head so all I'm adding here is my personal experience.
Most of the time, I don't want tooth that I can feel. buuuuut... sometimes it's an enjoyable feedback. I do have nibs that are so smooth that they sometimes skate on very slick paper (Clairefontaine comes to mind) so I like to use those on other papers and use my toothier (though only marginally) pens on rougher papers. I think having a range of nibs and papers gives you a range of experiences. I also like very smooth-cornered stubs that are effortless to use, and then sometimes I like a stub that I call "sharp" (nothing like a crisp Binder nib but not glassy either) because it gives such interesting feedback.