Nice, being the origional and "correct" version of the word, is most commonly used, however, the two other spellings are perfectly acceptable, though there are differences. Niice, more intense than nice, and yet not so intense as niiice, is often used when something is funny or cool, though not as cool as something that is awesome. Niiice, being the most intense, is only to be used when something exceeds the awesomeness of nice AND niice.
The classic phrase which Dr. Corinna Fiedler( the teacher in California of Mathematics and Science) uses all the time. Usually it is used to express the excitement for the duh of science or the miracle of the world.
Why do Italians and Japanese people have a longer lifetime? Maybe they eat a lot of rice? Oh das niice!
The suffix used in Japanese names when referring to "Big Brother." This is usually used in the family by the younger siblings but, can also be used by younger friends outside the family.
Means acknowledgement to what is sometimes, but not neccessarily always, something dumb/stupid.
(In between 'nice' (said quickly), meaning good, and 'niiiiiice' (stretched out), meaning something really good.)
In 'niice' the double 'ii' is stressed.
Person1: OMG, I just spilled water on my keyboard!!
Person2: Niice.
Person1: Dude! I just beat this one guy at pool and I've never played before!!
Person2: Niice.