Why not, instead of "I am contacting you regarding the issue you raised in your letter of June 12," write "The war in Iraq is indeed an act of imperialistic madness perpetrated by a semi-literate crackpot, as you note in your letter of June 12, but..."
My English teacher Mrs. Noble used to say, "They already know you are writing, because they have your letter in their hand, so don´t tell them you are writing to thank them, just thank them." Of course she was an old lady. GDDrew is quite correct, of course, but I would prefer, instead of "I write to inform you that your dog died after his plastic surgery, but the corpse was beautiful", a more direct version:
"Dear Ms. Jones: We did everything we could, but your dog died after his plastic surgery. On the other hand, his corpse was beautiful."
I once worked for an organization that received fifty thousand dollars from a rich contributor. The director wrote "I write with our thanks..." The secretary, who was not too bright, couldn´t read his handwriting, and typed a letter to the donor reading, "I write without thanks..." Perhaps the director should have written "Dear Mr. Jones: Your stupendous and generous gift of $50,000 for the widows of bilingual firemen killed while drinking ice cream sodas has made everyone here feel humble, but proud...?" or something like that.