I believe romaji came from the japanese word for "rome" − ローマ which in turn came from the original latin word for rome/roman which was Roma, *not* Rome/Roman.
(Yeah, "romanji" kind of gets on my nerves as well... The bad thing is, people see others using it, and then everyone starts using it without knowing any better.)
Have a textbook or grammar book that you find particularly helpful? What about a learning tip to share with others?