Hello I am thinking about getting either a cairn terrier, or a westie AND I NEED HELP! the problem is those dogs are my favorite kinds but i dont know which is more of a family dog. I live with two teenagers and my husband. We live near coyotes and a busy road. WHICH ONE IS BETTER PLEASE TELL!!!!!!!!!!!!!!!!!!

I dont think its a case of 'which ones better' but more 'which ones right for you' :) Do research on them both (books, net) , find breeders and go to shows (crufts) there you can ask about the breed and they may advise you on which ones best. These websites might help. (Sorry.. I dont know much about those breeds!):
http://www.dogbreedinfo.com/westhighland.htm

http://www.dogbreedinfo.com/cairnterrier.htm

i would think looking at the question this person is n't in the UK so going to Crufts wouldn't be an option :d.  I'm sure that someone will come along shortly re. the KC in your country so that they can give you names of breeders to enquire from.