As per my view add many keywords in anchor tag or Meta tag does not increase ranking or traffic. Because it is just way to high light our details for search engine. And if you do it more than it requires then search engine counts it as a keywords stuffing and it is possible to banned website.
in my opinion all have some importance themselves. First 2 tag options will be helpful for yahoo and bing and the third one will be useful to make your web site impressive and friendly user.