Endding a letter

Kind Regards
============
"kind regards" is a polite ending to a letter.
When you give your regards it means you are thinking of them.
Kind regards means you are thinking good thoughts.

This can be a nice ending for most personal letters.



Warm regards
============
Warm regards,...use for those who are close to you...good friends, family, associates

The difference here is that "warm" implies more "affection" for the person.

Some native speakers felt uncomfortable ending a business letter with a declaration of love/affection.


Best Regards
============
For business letters he usually end them using "Best regards".
This means giving them your best thoughts which is more appropriate.

You could also just end a business letter with "Regards".


Ref:
http://www.usingenglish.com/forum/ask-teacher/50991-kind-regards.html
http://www.englishforums.com/English/WarmRegards/wmzg/post.htm


Yours faithfully
================
Letters which begin Dear Sir(s) or Dear Madam
usually finish Yours faithfully in British English.


Yours sincerely
===============
Formal letters which begin with the person's name
(e.g. Dear Miss Hawkins, Dear Perter Lewis)
usually finish Yours sincerely.


Sincerely yours or Sincerely
============================
Common American endings are Sincerely yours or Sincerely.


With best wishes
================
In formal letters, many people put a closing formula befor Yours ....,
especially when writing to people they know:
common expressions are With best wishes and With kind regards.

Ref: หนังสือ Practical English Usage หัวข้อที่ 146.7