Most people recommend that when acquiring links one should vary the anchor text a lot. But, it that really natural? For example, if a site sells "widgets", is it natural to have links with many different modifiers like, unique, pretty, cheap, affordable, trendy, modern, fun, red, blue, etc.
There must be a point when it becomes unnatural, and could potentially hurt you. What do you think?
It's more detrimental to have the same anchor text multiple times than it is to different anchor text. You could use 3 and 4 word terms in your anchor text to try to help rank for many terms.
For example, the term 'long red widgets sale' will help rank for the following terms:
long red widgets sale long red widgets red widgets red widgets sale widgets sale
By combining primary keywords in your anchor text (have a few that just say 'red widgets') with more long tail terms you will get a good variation of keywords while still ranking well for your primary keywords without looking overly spammy.