Am I an Advisor or an Adviser? Well, usually I say consultant. As for the ‘A’ word, well, my clients don’t seem to care, but I prefer Advisor. Just seems to look better on the page.
However, we should be certain. I did a little digging and really like this answer from Bart Eden on Yahoo Answers:
Merriam Webster says the words are synonymous, as does the American Heritage Dictionary, the Random House Unabridged Dictionary, Roget’s Thesaurus, and Princeton’s WordNet. [...] The Columbia Guide to Standard American English states that “both spellings are standard”. It does not appear that the agentive ending –er or –or has any semantic meaning in the case of either term.
He also did a Google search and found advisor had about a 4-to-1 majority in mentions over adviser. Thanks Bart.
So there you have it. If you have any doubt at this point, I suggest you take it under advisement.