If you know of any specifics, feel free to list them here, and I'll compile. So far I've got Ravenwood's comments, and a few of my own.
Roy uses 'kimi' - an informal, affectionate form - when speaking to Edward (and possibly Alphonse?); uses 'ore' speaking to Hughes; used 'omae' during Nina situation in alley, possibly as a way to harshly jerk Ed back to attention
Edward uses 'anta' - mildly formal, but polite - when speaking to Roy; also uses titles more than proper name; uses 'ore' otherwise, except in episode 1 & 2, when he used more polite terms with Rose while asking for favor (?)
Alphonse uses 'niisan' exclusively when referring to Edward; uses 'boku' exclusively as first-person reference
Hawkeye - uses 'watashi' exclusively; refers to Edward and Alphonse with -kun honorific
Furman - called Edward 'boss'; uses 'ananta' when speaking to superior officers
Bradley - uses 'watashi' exclusively
Hughes - uses 'ore' exclusively; called Edward 'Ed'
Armstrong - refers to Winly and Pinako with -dono honorific
...That's all I can think of for now. If anyone has corrections or additions, let me know. Thanks.