Dear Mr. Crawford:
I would like to thank you once again for the fine offer which you made to me for a position of Software Developer reporting to Mr. Gupta. I was impressed with your company and the manner in which my visit was handled.
Unfortunately, I must inform you that I find it necessary to decline your offer. I am accepting a position with the XYZ in Seattle. Their training program will enable me to pursue my engineering interests immediately and to attend graduate school in the area.
I appreciate your interest on my behalf and wish to express my thanks again for all of your courtesies.
Very truly yours,