1.is taxonomy do caching ? i do a form that user needs to fill his personal infomation and that include a street name, i wonder how to do it, in taxonomy or in cck text field... what is better?
what is the best way to do a form dropdown options of known-non changing options? like choose color: red,green,blue.orange,gray ... should i use function and call to array? variable_set/get()? taxonomy vocab?
if i do a form for user that will not send to email its just need to add a node or stuff like that, is webform is a better alternative to the cck module?
taxonomy does no caching afaik. To have adress etc info for user i 'd use profile module in core. (you use d6 or d7?) ,
to 1. simple list of non-chaning option which does not need to maintained elsewhere (db/file) you use cck text field and provide values to choose from. Of course for many values, a cck taxonomy field is nice , because there are good import modules (taxonomy_csv and _xml)
question 2 i find hard to understand, pls elaborate a bit