At my last stay, I had commented the reservation and emailed the hotel noting that this was a special anniversary trip.

Was given a a wonderful top floor upgraded room, $50 restaurant dining credit, two free in-room movies, and a very nice handwritten note signed by the GM and sales manager.

Very nice.

And shrewd on the hotel's part, because we ended up spending more F&B than we would have otherwise.

If it's truly a special occasion and I'd like to request (the key word is "request" - politely, respectfully, humbly) an upgrade or any recognition that "the hotel might be able to do," I usually FAX the GM about a week before. Over the years, I've found a fax works better than an email in most (but obviously not all) cases.